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15 tháng 8 2023

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a, Xét \(\Delta\)ABC có: AB2 + AC2 = 62 + 4,52 = 56,25  (cm2)

                        BC2 = 7,52 = 56,25  (cm2)

AB2 + AC2 = BCvậy tam giác ABC vuông tại A (đpcm) 

SinC = 6 : 7,5  =0,8 ⇒ \(\widehat{C}\) = 53,130 ⇒ \(\widehat{B}\) = 900 - 53,130 = 36,870

b, Dựng hình chữ nhật ABCD, chiều cao AH, DK, và đường thẳng d đi qua D song song với BC  như hình vẽ ta có

SABC = SBDC ⇒ AH = DK 

Lây 1 điểm bất M kỳ di động trên đường thẳng d ta có:

SBDC = SMBC  (vì hai tam giác có chiều cao bằng nhau và chung cạnh đáy BC)

⇒ SABC = SMBC

Kết luận khi M di động trên đường thẳng d thì diện tích tam giác MBC luôn bằng diện tích tam giác ABC

 

 

 

 

 

 

 

 

 

17 tháng 10 2016

English is not math, Okay!

17 tháng 10 2016

NO. OK?

Đọc đoạn văn sau và chọn câu trả lời đúng cho các câu hỏi. (0,8 điểm)Air pollution is a serious problem in many cities. Motor vehicles, factories and other sources create so much air pollution that it may hang in the air like dirty fog. Air pollution threatens the health of the people who live in cities. City wastes cause water pollution when they are poured into the waterways. These wastes kill fish and make some areas unfit for swimming. In addition, many large cities have...
Đọc tiếp

Đọc đoạn văn sau và chọn câu trả lời đúng cho các câu hỏi. (0,8 điểm)

Air pollution is a serious problem in many cities. Motor vehicles, factories and other sources create so much air pollution that it may hang in the air like dirty fog. Air pollution threatens the health of the people who live in cities. City wastes cause water pollution when they are poured into the waterways. These wastes kill fish and make some areas unfit for swimming. In addition, many large cities have difficulties in disposing of their garbage. The amount of garbage grows each year, but places to put it are quickly filling up. Citizens, governments, industries, scientists, and business people must work together in different ways to gradually reduce pollution. For example, most cities have introduced recycling programs, which cut down on garbage and the space needed to store it. Residents separate recyclable products from garbage, and city governments provide drop-off cities or pick up the products from homes.

1. What is the main idea of the passage?

A. Air pollution is a serious problem in all cities.      B. Air pollution is a serious problem in countries.

C. Air pollution is a serious problem in many cities.

D. Air pollution is a serious problem with the governments.

2. According to the passage, city wastes cause ________.

A. air pollution                  B. water pollution    C. soil pollution       D. noise pollution

3. What does the word "it" in the passage refer to?

A.        garbage                 B. pollution             C. water                  D. problem

4. The word "different" is closest in meaning to ________.

A. like                                B. same                  C. similar                D. various

3
5 tháng 12 2021

1. What is the main idea of the passage?

A. Air pollution is a serious problem in all cities.      B. Air pollution is a serious problem in countries.

C. Air pollution is a serious problem in many cities.

D. Air pollution is a serious problem with the governments.

2. According to the passage, city wastes cause ________.

A. air pollution                  B. water pollution    C. soil pollution       D. noise pollution

3. What does the word "it" in the passage refer to?

A.        garbage                 B. pollution             C. water                  D. problem

4. The word "different" is closest in meaning to ________.

A. like                                B. same                  C. similar                D. various

5 tháng 12 2021

C

A

a

d

 

Đọc đoạn văn sau và chọn câu trả lời đúng cho các câu hỏi. (0,8 điểm)In Western countries, electricity, gas, and water are not luxuries but necessities. Companies now realize that consumers want products that will not only work effectively, but also save money.            For most North American households, lighting accounts for 10 percent to 15 percent of the electricity bill. However, this amount can be reduced by replacing an ordinary 100-watt bulb with an energy-saving...
Đọc tiếp

Đọc đoạn văn sau và chọn câu trả lời đúng cho các câu hỏi. (0,8 điểm)

In Western countries, electricity, gas, and water are not luxuries but necessities. Companies now realize that consumers want products that will not only work effectively, but also save money.

            For most North American households, lighting accounts for 10 percent to 15 percent of the electricity bill. However, this amount can be reduced by replacing an ordinary 100-watt bulb with an energy-saving bulb. These bulbs use a quarter of the electricity of standard bulbs and last eight times longer. Therefore consumers can save about US $7 to US $21 per bulb.

            In Europe, there is a labeling scheme for refrigerators, freezers, washing machines and tumble dryers. The label tells the consumers how much energy efficiency each model has, compared with other appliances in the same category.

            Ultimately, these innovations will save money as well as conserve the Earth’s resources.

 

1. What kinds of products do consumers want?

     ……............................……………….............………………………………………………………………

2. What can we do to spend less on lighting?

     ………………......................................………………………………………………………………………

3. Does an energy-saving bulb use a quarter of the electricity of a standard bulb?

     ……………………………………....................................…………………………………………………

4. What is the purpose of the labeling scheme?

1
21 tháng 10 2021

In Western countries, electricity, gas, and water are not luxuries but necessities. Companies now realize that consumers want products that will not only work effectively, but also save money.

            For most North American households, lighting accounts for 10 percent to 15 percent of the electricity bill. However, this amount can be reduced by replacing an ordinary 100-watt bulb with an energy-saving bulb. These bulbs use a quarter of the electricity of standard bulbs and last eight times longer. Therefore consumers can save about US 7toUS7toUS21 per bulb.

            In Europe, there is a labeling scheme for refrigerators, freezers, washing machines and tumble dryers. The label tells the consumers how much energy efficiency each model has, compared with other appliances in the same category.

            Ultimately, these innovations will save money as well as conserve the Earth’s resources.

1. What kinds of products do consumers want?

    Consumers want products that will not only work effectively, but also save money. ……............................……………….............………………………………………………………………

2. What can we do to spend less on lighting?

    We can replace an ordinary 100-watt bulb with an energy-saving bulb.  ………………......................................………………………………………………………………………

3. Does an energy-saving bulb use a quarter of the electricity of a standard bulb?

     ………………Yes, it does ……………………....................................…………………………………………………

4. What is the purpose of the labeling scheme?

The label tells the consumers how much energy efficiency each model has, compared with other appliances in the same category.

13 tháng 1 2018

còn tùy vào các bạn khác. nếu họ cao điểm hơn bạn thì ko dc. và ngược lại

13 tháng 1 2018

bạn ơi tùy theo từng nơi có nơi thì lấy điểm từ cao xuống thấp,có nơi lấy theo thang điểm.bạn sẽ đậu hoặc không.mình chỉ biết vậy thôi còn phụ thuộc vào thầy cô giáo trường cậu .mình cũng thi ioe đó trường mình thì lấy điểm từ cao xuống thấp.chúc bạn may mắn nhé

7 tháng 9 2021

Công thức chuyển câu chủ động sang câu bị động các bạn học theo bảng dưới đây nhé!

Thì

Chủ động

Bị động

Hiện tại đơn

S + V(s/es) + O

S + am/is/are + P2

Hiện tại tiếp diễn

S + am/is/are + V-ing + O

S + am/is/are + being + P2

Hiện tại hoàn thành

S + have/has + P2 + O

S + have/has + been + P2

Quá khứ đơn

S + V(ed/Ps) + O

S + was/were + P2

Quá khứ tiếp diễn

S + was/were + V-ing + O

S + was/were + being + P2

Quá khứ hoàn thành

S + had + P2 + O

S + had + been + P2

Tương lai đơn

S + will + V-infi + O

S + will + be + P2

Tương lai hoàn thành

S + will + have + P2 + O

S + will + have + been + P2

Tương lai gần

S + am/is/are going to + V-infi + O

S + am/is/are going to + be + P2

Động từ khuyết thiếu

S + ĐTKT + V-infi + O

S + ĐTKT + be + P2

và ngược lại

Câu VIII . Đọc đoạn văn sau và chọn câu trả lời đúng cho các câu hỏi. (0,8 điểm)Tomorrow, Linda - my best friend- is going to celebrate her 20th birthday. I am going tomake her a cake and a beautiful birthday card. I will also buy her a big bunch of roses. I thinkthat it will be a great surprise for her. Apart from me, there are going to be only ten otherpeople attending the party. They are her neighbors who I have already known. Linda hasnineteen classmates but they will not...
Đọc tiếp

Câu VIII . Đọc đoạn văn sau và chọn câu trả lời đúng cho các câu hỏi. (0,8 điểm)
Tomorrow, Linda - my best friend- is going to celebrate her 20th birthday. I am going to
make her a cake and a beautiful birthday card. I will also buy her a big bunch of roses. I think
that it will be a great surprise for her. Apart from me, there are going to be only ten other
people attending the party. They are her neighbors who I have already known. Linda has
nineteen classmates but they will not come as she has given another party at school. To tell the
truth, I am quite comfortable with this because I am always nervous when I have to talk to new
people.
As Linda’s closest friend, I will come early to help her prepare for the party. We will
have to move her bed to her parents’ room because it takes too much space. We will move the
bonsai from the balcony into her room to make it more beautiful. I really hope that the party
will be a pleasant one.
1. What does the passage mainly discuss?
A. A birthday present. B. Attending a birthday party.
C. Preparation for a birthday party. D. Activities in a birthday party.
2. According to the passage, how many people will come to Linda’s party?
A. 10 B. 11 C. 16 D. 19
3. What does the word this in paragraph 1 refer to?
A. Linda’s classmate.
B. The school.
C. The fact that Linda’s classmates will not join the party.
D. The fact that there will be only ten people in the party.
4. Where exactly will the party held?
A. In her parents’ room. B. In the balcony. C. In the living room. D. In Linda’s
room.

 

1
7 tháng 2 2022

3. What does the word this in paragraph 1 refer to?
A. Linda’s classmate.
B. The school.
C. The fact that Linda’s classmates will not join the party.
D. The fact that there will be only ten people in the party.

9 tháng 7 2018

No, I do not hate you

kb nhé

9 tháng 7 2018

bạn có ghét tôi ko ? 

trả lời : yes i do

28 tháng 5 2021

6 A (câu hỏi đuôi)

7 A (moon là vật duy nhất => dùng the)

8 B (interested in)

9 C (fond of V-ing)

10 A (often dấu hiệu HTĐ => động từ cần chia)

11 B (tình huống xen vào là quá khứ, nên hành động phải ở hiện tại tiếp diễn)

12 A (câu đk loại I)

13 B (book là danh từ chỉ vật đi với tình từ đuôi ing)

14 C (2 vế trái ngược nhau)

15 B (dịch nghĩa)

16 B (điều ước quá khứ , dùng hadn't + V2)

17 C (diễn tả sự suy đoán không chắc chắn)

18 A (bị động có dạng tobe + V2 )

19 D (dịch)

20 C (advise sb to V)

21 A (so sánh với tính từ ngắn(

22 C make st adj

23 D (spent time V-ing)

24 A (dịch)

25 A (protect st from)

26 A (đại từ quan hệ thay thế cho vật)