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14 tháng 12 2016

Cho một hình chữ nhật mà chiều rộng của nó là một nửa  chiều dài. Tỉ lệ giữa chu vi của hình chữ nhật với chiều rộng của nó là ?

Bài giải:

Gọi chiều rộng là: R; chiều dài là D; Chu vi là CV của hình chữ nhật

Theo đề bài ta có: R=1/2D. Suy ra D=2R                                      

    Mà chu vị hình chữ nhật là: CV = (D+R)x2.                              

Tỉ lệ giữa chu vi của hình chữ nhật với chiều rộng là: CV:R  = (2R +R)x2 : R

                                                                                       = 3Rx2:R =6

   Đáp án: 6                                                                                    

28 tháng 5 2015

so sorry . I dont understand

 

28 tháng 5 2015

Giải quyết từng tập thể dục bằng cách sử dụng tỷ lệ vàng\(\left(1+\sqrt{5}\right)\) : 2.
Tỉ lệ giữa chiều cao: chiều rộng của một vườn hoa bằng với tỷ lệ vàng. Chiều rộng của khu vườn là 14 feat. Tìm chiều dài của khu vườn. Thể hiện câu trả lời của bạn trong hình thức đơn giản nhất và triệt để ở bàn chân

câu 1: A rectangle has a length of 60cm and a width of 30cm. It is cut into 2 indentical squares, 2 identical rectangles and a shaded small square. Find the area of the shaded square. Find the area of the shaded square. câu 2.The number of ordered pairs (x; y) where x, y ∈ N* such that x2y2 - 2(x + y) is perfect square is .......... câu 3.Let ABCD be the square with the side length 56cm. If E and F lie on CD, C respectively such that CF = 14cm and EAF = 45o then CE = ........cm. câu...
Đọc tiếp

câu 1: A rectangle has a length of 60cm and a width of 30cm. It is cut into 2 indentical squares, 2 identical rectangles and a shaded small square. Find the area of the shaded square.
Find the area of the shaded square.
Đề thi violympic toán tiếng anh lớp 8 vòng 10
câu 2.The number of ordered pairs (x; y) where x, y ∈ N* such that x2y2 - 2(x + y) is perfect square is ..........

câu 3.Let ABCD be the square with the side length 56cm. If E and F lie on CD, C respectively such that CF = 14cm and EAF = 45o then CE = ........cm.

câu 4.

Given P(x) = (x2 - 1/2 x - 1/2)1008
If P(x) = a2016x2016 + a2015x2015 + ..... + a1x + a0
then the value of the sum a0 + a2 + a4 + .... + a2014 is ...........

Write your answer by decimal in simplest form câu 5.Let ABC be an isoceles triangle (AB = AC) and its area is 501cm2. BD is the internal bisector of the angle ABC (D ∈ AC), E is a point on the opposite ray of CA such that CE = CB. I is a point on BC such that CI = 1/2 BI. The line EI meets AB at K, BD meets KC at H. Find the area of the triangle AHC. câu 6. all roots of the polynomial P(x) = x2 + 5x - 1 are also roots of the polynomial Q(x) = x3 + ax2 + bx + c then the value of a + b + 6c is ............ câu 7.Suppose that the polynomial f(x) = x5 - x4 - 4x3 + 2x2 + 4x + 1 has 5 solutions x1; x2; x3; x4; x5. The other polynomial k(x) = x2 - 4.
Find the value of P = k(x1) x k(x2) x k(x3) x k(x4) x k(x5) câu 8.The smallest value of Đề thi violympic toán tiếng anh lớp 8 vòng 10 is ............. câu 9.Let ABCD be a trapezoid with bases AB, CD and O be the intersection of AC and BD. If the areas of triangle OAB, triangle OCD are 16cm2, 40cm2respectively and M is the midpoint of BD, then the area of the triangle AMD is .........cm2. câu 10.Bottle A contains 15% syrup. Bottle B contains 40% syrup. When these 2 bottles of syrup are mixed, the syrup content is 30% and the total volume is 600ml. How much syrup is in the bottle A at first? câu 11.Let ABCD.A'B'C'D' be a cube with AC' = √3cm. Find the total surface area of this cube. câu 12.Let ABC be a triangle with AB = 3cm, AC = 7cm. The internal bisector of the angle BAC intersects BC at D. The line passing through D and parallel to AC cuts AB at E. Find the measure of DE. câu 12.Given two numbers x, y such that (4y2 - 12y + 25)(4x2 + 6x + 4) = 28
The ratio of y to x is ........ câu 13.Mr.Joseph drives car from A to B at a constant speed. If the speed of the car is increased by 20%, it takes him one hour less than the usual time. If he drives at the constant speed for the first 100km before increasing the speed by 30%, it also takes him one hour less than the usual. The distance of AB is ..........km. câu 14.A triangle ABC has  = 120o and the bisector AD (D ∈ BC). If AB = 40cm, AD = 30cm, then AC = ..... cm. câu 15.As shown in the figure, the length of BE is .............
Đề thi violympic toán tiếng anh lớp 8 vòng 10 câu 16.

Let f(x) the polynomial given by f(x) = (1 + 2x + 3x2 + 4x3 + 5x4 + 84x5)
Suppose that f(x) = ao + a1x + a2x2 + ..... + ..... + a50x50.
The value of T = a1 + a2 + .... + a50 is .........

  • a. 9910 - 1
  • b. 9910
  • c. 10010
  • d. 10010 - 1
  • câu 17.Find the area of the trapezoid ABCD, BC // AD, AB = CD = 5cm, BC = 10cm, AD = 16cm.
    The area of the trapezoid ABCD is .........cm2.
  • câu 18.Find the least possible value of A = 4x2 - 3x + 1/4x + 2015, where x varies in the set of positive real numbers. The least possible value of A is
  • câu 19.
0
12 tháng 1 2022

????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????

12 tháng 1 2022
Nose this my is các anh chị giải dùm em với
2 tháng 2 2017

12 nha ban

11 tháng 2 2017

12 nha 

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 55 to 64. Overpopulation, the situation of having large numbers of people with too few resources and too little space, is closely associated with poverty. It can result from high population density, or from low amounts of resources, or from both. Excessively high population densities put stress on available resources. Only a certainnumber of people...
Đọc tiếp

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 55 to 64.

Overpopulation, the situation of having large numbers of people with too few resources and too little space, is closely associated with poverty. It can result from high population density, or from low amounts of resources, or from both. Excessively high population densities put stress on available resources. Only a certainnumber of people can be supported on a given area of land, and that number depends on how much food and other resources the land can provide. In countries where people live primarily by means of simple farming, gardening, herding, hunting, and gathering, even large areas of land can support only small numbers of people because these labor-intensive subsistence activities produce only small amounts of food.
In developed countries such as the United States, Japan, and the countries of Western Europe, overpopulation generally is not considered a major cause of poverty. These countries produce large quantities of food through mechanized farming, which depends on commercial fertilizers, large-scale irrigation, and agricultural machinery. This form of production provides enough food to support the high densities of people in metropolitan areas.
A country’s level of poverty can depend greatly on its mix of population density and agricultural productivity. Bangladesh, for example, has one of the world’s highest population densities, with 1,147 persons per sq km. A large majority of the people of Bangladesh engage in low-productivity manual farming, which contributes to the country’s extremely high level of poverty. Some of the smaller countries in Western Europe, such as the Netherlands and Belgium, have high population densities as well. These countries practice mechanized farming and are involved in high-tech industries, however, and therefore have high standards of living.
At the other end of the spectrum, many countries in sub-Saharan Africa have population densities of less than 30 persons per sq km. Many people in these countries practice manual subsistence farming; these countries also have infertile land, and lack the economic resources and technology to boost productivity. As a consequence, these nations are very poor. The United States has both relatively low population density and high agricultural productivity; it is one of the world’s wealthiest nations.
High birth rates contribute to overpopulation in many developing countries. Children are assets to many poor families because they provide labor, usually for farming. Cultural norms in traditionally rural societies commonly sanction the value of large families. Also, the governments of developing countries often provide
little or no support, financial or political, for family planning; even people who wish to keep their families small have difficulty doing so. For all these reasons, developing countries tend to have high rates of population growth.

From "Poverty" by Thomas J. Corbett

Which of the following is given a definition in paragraph 1?

  • A. Poverty
  • B. Population density
  • C. Overpopulation
  • D. Simple farming
  • Câu 2:

    What will suffer when there are excessively high population densities?

    • A. Available resources
    • B. Farming methods
    • C. Land area
    • D. Skilled labor
  • Câu 3:

    The phrase “that number” in paragraph 1 refers to the number of ______.

    • A. resources
    • B. countries
    • C. people
    • D. densities
  • Câu 4:

    In certain countries, large areas of land can only yield small amounts of food because ______.

    • A. there is an abundance of resources
    • B. there is no shortage of skilled labor
    • C. there are small numbers of laborers
    • D. there is lack of mechanization
  • Câu 5:

    Bangladesh is a country where the level of poverty depends greatly on ______.

    • A. population density in metropolitan areas
    • B. both population density and agricultural productivity
    • C. its population density only
    • D. its high agricultural productivity
  • Câu 6:

    The phrase “engage in” in paragraph 3 is closest in meaning to ______.

    • A. escape from
    • B. look into
    • C. give up
    • D. participate in
  • Câu 7:

    The word “ infertile ” in paragraph 4 probably means ______.

    • A. impossible
    • B. unproductive
    • C. disused
    • D. inaccessible
  • Câu 8:

    Which of the following is TRUE, according to the passage?

    • A. In sub-Saharan African countries, productivity is boosted by technology.
    • B. There is no connection between a country’s culture and overpopulation.
    • C. All small countries in Western Europe have high population densities.
    • D. In certain developed countries, mechanized farming is applied.
  • Câu 9:

    Which of the following is a contributor to overpopulation in many developing countries?

    • A. High-tech facilities
    • B. High birth rates
    • C. Economic resources
    • D. Sufficient financial support
  • Câu 10:

    Which of the following could be the best title for the passage?

    • A. High Birth Rate and its Consequences
    • B. Poverty in Developing Countries
    • C. Overpopulation: A Worldwide Problem
    • D. Overpopulation: A Cause of Poverty
2
2 tháng 10 2019

Đáp án nè bạn:

1-C

2-A

3-C

4-D

5-B

6-D

7-B

8-D

9-B

10- D

2 tháng 10 2019

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 55 to 64.

Overpopulation, the situation of having large numbers of people with too few resources and too little space, is closely associated with poverty. It can result from high population density, or from low amounts of resources, or from both. Excessively high population densities put stress on available resources. Only a certainnumber of people can be supported on a given area of land, and that number depends on how much food and other resources the land can provide. In countries where people live primarily by means of simple farming, gardening, herding, hunting, and gathering, even large areas of land can support only small numbers of people because these labor-intensive subsistence activities produce only small amounts of food.
In developed countries such as the United States, Japan, and the countries of Western Europe, overpopulation generally is not considered a major cause of poverty. These countries produce large quantities of food through mechanized farming, which depends on commercial fertilizers, large-scale irrigation, and agricultural machinery. This form of production provides enough food to support the high densities of people in metropolitan areas.
A country’s level of poverty can depend greatly on its mix of population density and agricultural productivity. Bangladesh, for example, has one of the world’s highest population densities, with 1,147 persons per sq km. A large majority of the people of Bangladesh engage in low-productivity manual farming, which contributes to the country’s extremely high level of poverty. Some of the smaller countries in Western Europe, such as the Netherlands and Belgium, have high population densities as well. These countries practice mechanized farming and are involved in high-tech industries, however, and therefore have high standards of living.
At the other end of the spectrum, many countries in sub-Saharan Africa have population densities of less than 30 persons per sq km. Many people in these countries practice manual subsistence farming; these countries also have infertileland, and lack the economic resources and technology to boost productivity. As a consequence, these nations are very poor. The United States has both relatively low population density and high agricultural productivity; it is one of the world’s wealthiest nations.
High birth rates contribute to overpopulation in many developing countries. Children are assets to many poor families because they provide labor, usually for farming. Cultural norms in traditionally rural societies commonly sanction the value of large families. Also, the governments of developing countries often provide
little or no support, financial or political, for family planning; even people who wish to keep their families small have difficulty doing so. For all these reasons, developing countries tend to have high rates of population growth.

From "Poverty" by Thomas J. Corbett

Which of the following is given a definition in paragraph 1?

  • A. Poverty
  • B. Population density
  • C. Overpopulation
  • D. Simple farming

  • Câu 2:

    What will suffer when there are excessively high population densities?

    • A. Available resources
    • B. Farming methods
    • C. Land area
    • D. Skilled labor
  • Câu 3:

    The phrase “that number” in paragraph 1 refers to the number of ______.

    • A. resources
    • B. countries
    • C. people
    • D. densities
  • Câu 4:

    In certain countries, large areas of land can only yield small amounts of food because ______.

    • A. there is an abundance of resources
    • B. there is no shortage of skilled labor
    • C. there are small numbers of laborers
    • D. there is lack of mechanization
  • Câu 5:

    Bangladesh is a country where the level of poverty depends greatly on ______.

    • A. population density in metropolitan areas
    • B. both population density and agricultural productivity
    • C. its population density only
    • D. its high agricultural productivity
  • Câu 6:

    The phrase “engage in” in paragraph 3 is closest in meaning to ______.

    • A. escape from
    • B. look into
    • C. give up
    • D. participate in
  • Câu 7:

    The word “ infertile ” in paragraph 4 probably means ______.

    • A. impossible
    • B. unproductive
    • C. disused
    • D. inaccessible
  • Câu 8:

    Which of the following is TRUE, according to the passage?

    • A. In sub-Saharan African countries, productivity is boosted by technology.
    • B. There is no connection between a country’s culture and overpopulation.
    • C. All small countries in Western Europe have high population densities.
    • D. In certain developed countries, mechanized farming is applied.
  • Câu 9:

    Which of the following is a contributor to overpopulation in many developing countries?

    • A. High-tech facilities
    • B. High birth rates
    • C. Economic resources
    • D. Sufficient financial support
  • Câu 10:

    Which of the following could be the best title for the passage?

    • A. High Birth Rate and its Consequences
    • B. Poverty in Developing Countries
    • C. Overpopulation: A Worldwide Problem
    • D. Overpopulation: A Cause of Poverty
Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions from 1 to 10. Reading to oneself is a modern activity which was almost unknown to the scholars of the classical and medieval worlds, while during the fifteenth century the term "reading" undoubtedly meant reading aloud. Only during the nineteenth century did silent reading become commonplace. One should be wary, however, of assuming that silent reading came...
Đọc tiếp

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions from 1 to 10.

Reading to oneself is a modern activity which was almost unknown to the scholars of the classical and medieval worlds, while during the fifteenth century the term "reading" undoubtedly meant reading aloud. Only during the nineteenth century did silent reading become commonplace.

One should be wary, however, of assuming that silent reading came about simply because reading aloud was a distraction to others. Examinations of factors related to the historical development of silent reading have revealed that it became the usual mode of reading for most adults mainly because the tasks themselves changed in character.

The last century saw a steady gradual increase in literacy and thus in the number of readers. As the number of readers increased, the number of potential listeners declined and thus there was some reduction in the need to read aloud. As reading for the benefit of listeners grew less common, so came the flourishing of reading as a private activity in such public places as libraries, railway carriages and offices, where reading aloud would cause distraction to other readers.

Towards the end of the century, there was still considerable argument over whether books should be used for information or treated respectfully and over whether the reading of materials such as newspapers was in some way mentally weakening. Indeed, this argument remains with us still in education. However, whatever its virtues, the old shared literacy culture had gone and was replaced by the printed mass media on the one hand and by books and periodicals for a specialised readership on the other.

By the end of the twentieth century, students were being recommended to adopt attitudes to books and to use reading skills which were inappropriate, if not impossible, for the oral reader. The social, cultural and technological changes in the century had greatly altered what the term "reading" implied.

Question 1: Reading aloud was more common in the medieval world because:

A. people relied on reading for entertainment

B. silent reading had not been discovered

C. there were few places available for private reading

D. few people could read to themselves

Question 2: The word "commonplace" in the first paragraph mostly means:

A. for everybody's use B. most preferable

C. attracting attention D. widely used

Question 3: The development of silent reading during the last century indicated

A. an increase in the average age of readers

B. an increase in the number of books

C. a change in the nature of reading

D. a change in the status of literate people

Question 4: Silent reading, especially in public places, flourished mainly because of:

A. the decreasing need to read aloud

B. the development of libraries

C. the increase in literacy

D. the decreasing number of listeners

Question 5 It can be inferred that the emergence of the mass media and specialized reading materials was an indication of .

A. a decline of standards of literacy

B. a change in the readers' interest

C. an alteration in educationalists ’attitudes

D. an improvement of printing techniques.

Question 6: The phrase "a specialized readership" in paragraph 4 mostly means:

A. a requirement for readers in a particular area of knowledge

B. a limited number of readers in a particular area of knowledge

C. a reading volume for particular professionals

D. a status for readers specialized in mass media

Question 7: The phrase “oral reader" in the last paragraph mostly means a person who:

A. is good at public speaking

B. practices reading to an audience

C. takes part in an audition

D. is interested in spoken language

Question 8: All of the following might be the factors that affected the continuation of the old shared literacy culture EXCEPT .

A. the inappropriate reading skills B. the specialized readership

C. the diversity of reading materials D. the printed mass media

Question 9: Which of the following statements is NOT TRUE according to the passage?

A. Reading aloud was more common in the past than it is today.

B. Not all printed mass media was appropriate for reading aloud.

C. The decline of reading aloud was wholly due to its distracting effect.

D. The change in reading habits was partly due to the social, cultural and technological changes.

Question 10: The writer of this passage is attempting to .

A. explain how reading habits have developed

B. change people's attitudes to reading

C. show how reading methods have improved

D. encourage the growth of reading.

3

Bạn đăng trên box Anh nhé,Bạn đang đăng trên box Toán đấy

2 tháng 10 2019

Tham khảo

Câu 1. Đáp án D few people could read to themselves

Thông tin ở đầu đoạn 1:”Reading to………….reading aloud”. (Đọc thầm 1 mình là 1 hoạt động hiện đại mà hầu như không hề được biết đến đối với các học giả thời cổ điển và thời trung cổ,trong khi vào thế kỷ 15,nói đến đọc nghĩa là đọc lớn tiếng.)

Câu 2. Đáp án D widely used

Định nghĩa của commonplace: được sử dung rộng rãi,phổ biến thông dụng

Câu 3. Đáp án C a change in the nature of reading

Thông tin ở 2 đoạn 2:”examination of factors………….in character”. (Sự khỏa sát các yếu tố liên quan đến sự phát triển có tính lịch sử của việc đọc thầm đã trở thành lối đọc thông dụng đối với đa số người lớn vì bản thân việc đọc đã thay đổi bản chất.)

Câu 4. Đáp án C the increase in literacy

Thông tin ở đầu đoạn 3:”The lát century saw…………………to read aloud”: (Thế kỷ vừa qua chứng kiến 1 sự gia tăng, số người đọc tiềm năng giảm bớt và do vậy nhu cầu đọc lớn tiếng cũng giảm đi.)

Câu 5. Đáp án A a decline of standards of literacy

Thông tin ở cuối đoạn 4:”However,………..on the other”: Tuy nhiên dù lợi ích của việc đọc là gì đi nữa,thì cái nền văn hóa chia sẻ tri thức của ngày xưa cũng đã biến mất và bị thay thế bởi 1 nền báo chí và 1 bên là sách vở và các ấn phẩm định kỳ dành cho các độc giả chuyên ngành

Câu 6. Đáp án B a limited number of readers in a particular area of knowledge

Số đọc giả có giới hạn chuyên về 1 ngành kiến thức riêng biệt

Câu 7. Đáp án B practises reading to an audience (Đọc cho 1 số thính giả nghe)
Câu 8. Đáp án A the inappropriate reading skills (Kỹ năng đọc không phù hợp)
Câu 9. Đáp án C

The decline of reading aloud was wholly due to its distracting effect. Sự suy giảm việc đọc lớn tiếng la do tác dụng làm phiền người khác của nó

Câu 10. Đáp án A explain how reading habits have developed

Tác giả đã cố giải thích thói quen đọc đã thay đổi như thế nào