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Yen Nhi
21 tháng 4 2022 lúc 22:50

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Gọi `D` là trung điểm của `BH`

Kẻ `DF` vuông góc `AB` tại `D;DF=AB`

Xét `\triangleFDB` và `\triangleBAC`:

`DF=AB`

`\hat{FDB}=\hat{BAC}=90^o`

`DB=AC`

`=>\triangleFDB=\triangleBAC{c.g.c)`

`=>FB=BC;\hat{FBD}=\hat{BCA}`

`=>\hat{FBD}=90^o - \hat{ABC}=15^o`

`=>\hat{FBC}=\hat{ABC} - \hat{FBD} = 60^o`

Xét `\triangleBFC`, có: `FB=BC=>\triangleBFC` cân tại `B`

Mà `\hat{FBC}=60^o =>\triangleBFC` đều

`=>FC=FB=BC` (*)

Ta có: `F\in` trung trực `BH=>FH=FB` (**)

Từ (*)(**)`=>FH=FC=FB`

Xét `\triangleHFB`, có: `FH=FB=>\triangleHFB` cân tại `F`

Mà `\hat{HBF}=15^o =>\hat{HFB}=180^o -2\hat{HBF}=150^o`

Ta có: `\hat{HFC} + \hat{HFB} + \hat{BFC} = 360^o`

`=>\hat{HFC}=360^o - 150^o - 60^o`

`=>\hat{HFC}=\hat{HFB}=150^o`

Xét `\triangleHFC` và `\triangleHFB`:

`HF` chung

`FC=FB`

`\hat{HFC}=\hat{HFB}`

`=>\triangleHFC=\hat{HFB}(c.g.c)`

`=>\hat{FHC}=\hat{FHB}`

`=>\hat{BHC}=2\hat{FHB}=2\hat{FBH}=30^o`

`=>\hat{BHC}=30^o`

 

 

Tên Ko
26 tháng 7 2016 lúc 20:43

a) xét tam giác ABD và tam giác ACE có:

                   góc A:chung (gt)

                    góc AEC = góc BDA =90 độ (gt)

 suy ra tam giác ABD = tam giác ACE ( g.g )

tù đó suy ra: AE trên AD = AC trên AB và = AE . AB = AC . AD

Lan Anh
26 tháng 12 2016 lúc 16:21

V.

1. D.was --> did

2. B.to --> bỏ to

3. D.careless --> carelessly

4. B.brings --> bring

VI.

1. C.up

2. A.breakfast

3. drink

6. A.in

7. C.does

8. B.watches

9. B.at

10. D.favourite

Võ Minh Thắng
16 tháng 12 2016 lúc 20:09

my hobby is collecting comics. I started my hobby 2 years ago. My mother took me to the bookstore and bought some comics for me.I like reading comics for me. I like reading comics in my freetime because it helps me relax. I spend all lucky money to buy comics. I find this hobby interesting because comics make me funny and excited.

I hope that in the future, i'll have a big bookshelf of comics to read them.

Hơi ngắn, xin lỗi nhé !vui

Phạm Phương Linh
15 tháng 12 2016 lúc 17:40

I have many hobbies, but I like reading most. Books are always a good friend to me. It is a good way to improve my vocabularies by exposing many new words.I star to reading book when i in grade 3.my brother inspired me to do that.I usualy share my hobby with my friend and my english teacher.By reading, I get better at concentration because it requires me to focus on what I am reading for long periods. It also opens up the knowledge door for me. Reading books tell me about the world's history, let me see the structure of the brain, or bring me a story of Sherlock Holmes. I think reading is one of the most interesting indoors activity and I will keep this hobby forever.

33 Le Pham Phuong Quynh...
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Dân Chơi Đất Bắc=))))
10 tháng 1 2022 lúc 18:48

____Do________ you (get) ___get__________ up late this morning?

Hoang (not come) ________didn't come___________ home late yesterday evening.

What ___did__________ you (have)___have__________ for lunch yesterday?

Where _______did______ Nam (go) ______go_______ last summer?

Liz (help) ______helped_______ me a lot with my housework last week.

He (buy) ________bought___________ me some flowers last night.

I (get) __________got_________ a terrible headache last night.

He (knew) ________knew___________ him long time ago.

We (eat) _______will eat____________ some fish for dinner tomorrow.

My friends (travel) ______will travel_________ to Da Nang next week.

Last night, we (not watch) ______didn't watch_______________ TV.

My teacher (return) _______have returned______________ here soon

He (teach) ________taught_____________ us last year.

Her father (take) _____takes__________ her daughter to the dentist.

Mai (make) ______made_______________ a big cake yesterday.

There (be) _______has been______________ a storm here soon.

She (drink) _________drank____________ a lot of beer last night.

My mother (cook) _______will cook______________ dinner tonight.

Hai (not arrive) ___________hasn't arived__________ here soon.

______Are_________ you (give) _____giving__________ her a present?

Loan (help) ________helped__________ me do housework yesterday.

I (not have) ________didn't have_____________ any close friends last year.

They (not obey) _______didn't obey___________ their teacher last time.

Nguyễn Hương Giang
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O=C=O
7 tháng 2 2018 lúc 22:59

Sự phân bố dân cư :
- Dân cư Bắc Mỹ phân bố không đồng đều giửa phía tây và phía đông, miền bắc và miền nam.
- Mật độ dân số thấp nhất là phía bắc Canada và bán đảo A-la-xca dưới 1 người/km2 kế đó là miền núi Coóc-đi-e Hoa Kỳ.
- Mật độ dân số cao nhất là vùng đông bắc Hoa Kỳ: từ dải đất phía nam Hồ Lớn đến duyên hải Đại Tây Dương. Mật độ dân số trên 100 người/km2
- ¾ dân số Bắc Mỹ sống ở thành thị.
- Trong các năm gần đây, phân bố dân cư Bắc Mỹ có sự thay đổi nhất là trên lãnh thổ Hoa Kỳ, có sự chuyển dịch dân cư trên lãnh thổ Hoa Kỳ từ các vùng công nghiệp phía nam Hồ Lớn và Đông Bắc ven Đại Tây Dương hướng về phía nam và vùng duyên hải phía tây ven Thái Bình Dương do sự phát triển mạnh các ngành công nghiệp mới.

Cherry  anh
25 tháng 2 2018 lúc 20:21

*Giống nhau :

Cấu trúc điạ hình tương tự nhau đều chia làm ba phần: núi trẻ phía Tây, đồng bằng ở giữa, núi già ở phiá Đông.Địa hình kéo dài theo chiều kinh tuyến.

*Khác nhau:

-Bắc Mĩ:

+Phía Đông:núi già Apalat và sơn nguyên trên bán đảo Labrađa.

+Ở giữa: Đồng bằng trung tâm cao ở phía Bắc, thấp dần về phía Nam.

+Phía Tây:Hệ thống Cooc-đi-e cao trung bình (3000-4000m) và đồ sộ chiếm một nửa lục địa Bắc Mĩ.

-Trung và Nam Mĩ:

+Phía Đông sơn nguyên Guy-a-na và sơn nguyên Brazin.

+Ở giữa: là chuỗi đồng bằng nối liền nhau: Ô-ri-nô-cô-> Amadôn-> Laplata-> Pama. Các đồng bằng đều thấp, trừ đồng bằng Pama có điạ hình cao ở phía Nam.

Minh Thư Hồ
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Đỗ Ngọc nam
22 tháng 12 2021 lúc 20:27

1 c 2 d

 

Nguyễn Thị Ngọc Anh
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Luminos
23 tháng 12 2021 lúc 14:07

Question 1. Look! He ________ football now.

A. is playing              B. plays                      C. played                          D. was playing

 

Question 2. It’s very ________ of you to help me.

A. talkative               B. active                    C. nice                                D. confident

 

Question 3. Nam and Ba ________ ice cream at the moment.

A. eating                    B. is eating                C. was eating                         D. are eating

 

Question 4. Steve can deal with difficult exercises. He’s a __________ boy.

A. creative                 B. intelligent             C. sporty                           D. kind

 

Question 5. Please be ___________ when you have to use fire to cook.

A. handsome             B. clever                    C. careful                         D. reliable

 

Question 6. She is so ___________ that she doesn’t talk much to strangers.

A. reserved                B. clever                    C. active                           D. smart

 

Question 7. The part between the head and the body is the _________.

A. leg                          B. neck                       C. knee                            D. shoulder

 

Question 8. My friend, Lan is a ________ student. She always finishes homework on time.

A. hard-working       B. confident                 C. shy                               D. reliable

 

Question 9. What does your best friend look like?

A. He is funny          B. He is kind             C. He is clever                      D. He is handsome

 

Question 10. What’s your classmate like?

A. She’s patient        B. She’s beautiful        C. She’s tall                     D. She’s thin

 

Question 11. Peter __________ a straight nose and fair skin.

A. goes                       B. comes                    C. does                                   D. has

 

Question 12. Would you like _________ to the hospital to visit my mother?

A. to go                      B. going                     C. go                               D. will go

 

Question 13. _______ you _______ an English class tomorrow?

A. Do – have             B. Are – having        C. Will – having                   D. Is – have

 

Question 14. That girl has yellow hair. She has _______ hair.

A. black                     B. wavy                      C. blonde                               D. curly

 

Question 15. We should brush our ____________ twice a day.

A. feet                        B. teeth                      C. hair                                    D. toe

N    N
23 tháng 12 2021 lúc 14:07

Choose the letter A, B, C or D to complete the sentences

Question 1. Look! He ________ football now.

A. is playing              B. plays                      C. played                          D. was playing

 

Question 2. It’s very ________ of you to help me.

A. talkative               B. active                    C. nice                                D. confident

 

Question 3. Nam and Ba ________ ice cream at the moment.

A. eating                    B. is eating                C. was eating                         D. are eating

 

Question 4. Steve can deal with difficult exercises. He’s a __________ boy.

A. creative                 B. intelligent             C. sporty                           D. kind

 

Question 5. Please be ___________ when you have to use fire to cook.

A. handsome             B. clever                    C. careful                         D. reliable

 

Question 6. She is so ___________ that she doesn’t talk much to strangers.

A. reserved                B. clever                    C. active                           D. smart

 

Question 7. The part between the head and the body is the _________.

A. leg                          B. neck                       C. knee                            D. shoulder

 

Question 8. My friend, Lan is a ________ student. She always finishes homework on time.

A. hard-working       B. confident                 C. shy                               D. reliable

 

Question 9. What does your best friend look like?

A. He is funny          B. He is kind             C. He is clever                      D. He is handsome

 

Question 10. What’s your classmate like?

A. She’s patient        B. She’s beautiful        C. She’s tall                     D. She’s thin

 

 

 

Question 11. Peter __________ a straight nose and fair skin.

 

A. goes                       B. comes                    C. does                                   D. has

 

Question 12. Would you like _________ to the hospital to visit my mother?

A. to go                      B. going                     C. go                               D. will go

 

Question 13. _______ you _______ an English class tomorrow?

A. Do – have             B. Are – having        C. Will – having                   D. Is – have

 

Question 14. That girl has yellow hair. She has _______ hair.

 

A. black                     B. wavy                      C. blonde                               D. curly

 

Question 15. We should brush our ____________ twice a day.

A. feet                        B. teeth                      C. hair                                    D. toe

 

 

Tiếng Anh
23 tháng 12 2021 lúc 14:07

Choose the letter A, B, C or D to complete the sentences

Question 1. Look! He ________ football now.

A. is playing              B. plays                      C. played                          D. was playing

 

Question 2. It’s very ________ of you to help me.

A. talkative               B. active                    C. nice                                D. confident

 

Question 3. Nam and Ba ________ ice cream at the moment.

A. eating                    B. is eating                C. was eating                         D. are eating

 

Question 4. Steve can deal with difficult exercises. He’s a __________ boy.

A. creative                 B. intelligent             C. sporty                           D. kind

 

Question 5. Please be ___________ when you have to use fire to cook.

A. handsome             B. clever                    C. careful                         D. reliable

 

Question 6. She is so ___________ that she doesn’t talk much to strangers.

A. reserved                B. clever                    C. active                           D. smart

 

Question 7. The part between the head and the body is the _________.

A. leg                          B. neck                       C. knee                            D. shoulder

 

Question 8. My friend, Lan is a ________ student. She always finishes homework on time.

A. hard-working       B. confident                 C. shy                               D. reliable

 

Question 9. What does your best friend look like?

A. He is funny          B. He is kind             C. He is clever                      D. He is handsome

 

Question 10. What’s your classmate like?

A. She’s patient        B. She’s beautiful        C. She’s tall                     D. She’s thin

 

Question 11. Peter __________ a straight nose and fair skin.

A. goes                       B. comes                    C. does                                   D. has

 

Question 12. Would you like _________ to the hospital to visit my mother?

A. to go                      B. going                     C. go                               D. will go

 

Question 13. _______ you _______ an English class tomorrow?

A. Do – have             B. Are – having        C. Will – having                   D. Is – have

 

Question 14. That girl has yellow hair. She has _______ hair.

A. black                     B. wavy                      C. blonde                               D. curly

 

Question 15. We should brush our ____________ twice a day.

A. feet                        B. teeth                      C. hair                                    D. toe

 

TRƯƠNG CÁT NGUYÊN PHƯƠNG
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htfziang
16 tháng 1 2022 lúc 20:18

1. My brother and I don't like playing video games.
-> I don't like __playing video games and neither does my brother__

2. Drinking lots of water and fruit juices everyday is good for you

 

-> It's ____good for you to drink lots of water and fruit juices everyday___
3.Did Lan help her parents on the farm
-> Lan_____helped her parents on the farm, didn't she?___
4.Hoa and Minh will go to the zoo next week
-> Hoa will____go to the zoo next week and so does Minh___
5.Noone helped us do the math homework
->We did___the math homework by ourselves
6. Eating habits in Japan are different from France
-> Eating habits in France are not __the same as in Japan_

zero
16 tháng 1 2022 lúc 20:37

1 I don't likeplaying video games and neither does my brothe

2  It's good for you to drink lots of water and fruit juices everyday

3 Lanhelped her parents on the farm, didn't she?

4 Hoa willgo to the zoo next week and so does Minh

5 We didthe math homework by ourselves

6 Eating habits in France are not the same as in Japan

ngọc nọc nọc
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Dang Khoa ~xh
21 tháng 12 2021 lúc 19:09

1. Mr Tung, our English teacher (never/ be)________is never____________ late for lessons.

2. He (often/ clean)_________often cleans___________ his bedroom at the weekend.

3. My sister (never/ help)_____________never helps_______ me with my homework.

4. I (sometimes/ be)__________am sometimes__________ bored in the Maths lessons.

5. We (rarely/ watch)___________rarely wath_________ football on TV.

6. Tony (never/ play)______never plays______________ computer games with me.

7. We (usually/ be)_________are usually___________ at the sports centre on Sunday.

8. The school bus (always/ arrive)_________always arrives___________ at half past eight.