user-avatar
Maiducthang
2 năm trước
Cho tam giác ABC cân tại A.Tia phân giác BD,CE của góc B và C cắt nhau tại O.Hạ OK vuông góc AC,OH vuông góc AB.Chứng minh a)Tam giác BCD=tam giác CBE b)OB=OC c)OH=OK
Thích Trả lời Chia sẻ

Các câu hỏi liên quan

1. the class...at 7 o'clock in the morning 2, ...are you talking to?i am talking to my friend, thanh. 3, ...do you go to bed? at 9 o'clock. 4,...does nga have english? 5, ...lessons do you have today? 6. mai goes to school...a week. 7. how many....does hung have on wednesday? 8. i would like... a letter to america. 9.i want...a phone card. 10, i would like to send this latter...the USA. 11.alan and his friends...to tuan chau island last week. 12.they traveled to hanoi...bus. 13.we are going...ha long bay next sunday. 14.how...is it from here to hanoi? 15.what do you usually do...autumn? 16.what is the...like today? it's sunny and hot. 17. ...did you do last weekend?i went to the cinema. 18.where....you yesterday? 18.what do you usually do...spring? 19.there...a lot of flowers at the festival last week.

I. Choose the best answer A, B, C or D to complete each sentence. 1. The word with a different stress pattern from the others is …. A. unpolluted B. unbalanced C. unreasonable D. unlawful 2. Global communication was changed by…………….of the Internet. A. invent B. invention C. inventor D. invented 3. Air pollution, together with littering, has………many problems in our large cites today. A. caused B. made C. affected D. brought 4. Australia is a …….what the planet Earth will be like in 100 years’ time. A. exceptional B. scenic C. iconic D. unique 5. My brother had never been abroad ………he joined the army. A. since B. until C. during D. while 6. All our beautiful forests………if we do nothing to preserve them. A. will destroy B. will be destroyed C. would destroy D. would be destroyed 7. I’d be over the moon if I ……..a chance to go to Disneyland in California. A. have B. had C. will have D. would have 8. In message board you can……….messages pr post questions. A. raise B. arrive C. text D. leave 9. You shrug your shoulders means “……………….”. A. I’m hungry. B. I don’t know. C. I’m angry. D. Sorry. I need to go now. 10. Using music, codes or signs to communicate is called…….…communication. A. verbal B. non-verbal C. public D. non-public 11. I experienced one communication………in Japan when I didn’t understand their body. A. breakdown B. technique C.ability D. device 12. John managed……………..his family in England by using Zalo. A. contact B. to contact C. contacting D. contacts 13. We……….with each other by mobile phone in 2050. A. won’t be communicating B. aren’t communicating C. haven’t communicated D. aren’t going to communicate 14. The word with a different stress pattern from the others is …. A. helpless B. unless C. painless D. airless 15. Working hours will fall to under 35 a week, ………………? A. will they B. won’t they C. won’t it D. will it 16. My grandma…………….a lot of pleasure from gardening. A. does B. has C. makes D. gets 17. From 1856 to 1875, a remarkable……..of inventions was produced. A. diversity B. mixture C. variety D. collection 18. Do you think there……less conflict in the world if all people……the same language? A. would be/ spoke B. is/ spoke C. were/ speak D. is/ will speak 19. Thousands of people…….by natural disasters every year. A. are affected B. are affecting C. have affected D. were affected 20. -“No one was killed in the forest fire two days ago.” - “________.” A. Oh dear B. That’s shocking C. That’s a relief D. How terrible 21. We cannot present natural disasters, but we can……….for them. A. defeat B. invent C. struggle D. prepare 22. Hundreds of people were made…………after the flood. A. homeless B. helpless C. careless D. endless 23. Water.............make some aquatic animals die. A.pollution B.pollute C.polluted D.polluting II. Complete the sentences, using the correct forms of the verbs in brackets. 1. Goodbye, Mr. Quynh! I …………………(phone) you as soon as I arrive home. 2. Hundred of trees on street in Ha Noi……………………..(fall) in a sudden storm last night. 3. I ………...……(not seen) a more horrible flood than this since I ……….(live) in this area. 4.Listen! He (sing)......................... 5.Most people (leave)...............their houses before the volcano erupted 6.The lesson (start)....................at 7.00.am

2018 © Loga - Không Ngừng Sáng Tạo - Bùng Cháy Đam Mê
Loga Team