user-avatar
thuhang31
2 năm trước
Cho đtr (O) cố định. Gọi tam giác nhọn ABC trong đó BC không đổi, các đường cao BD và CE cắt nhau ở H cắt đtr (O) theo thứ tự M và N. a. C/m tứ giác BCDE nội tiếp b. C/m AB.AE = AD.AC c. Qua A kẻ dường thẳng song song với MN cắt đường thẳng BC ở K. C/m MN vuông góc AO và KA^(2) = KB.KC d. C/m bán kính đtr ngoại tiếp tam giác ADE không đổi.
Thích Trả lời Chia sẻ

Các câu hỏi liên quan

A. Circle the best option A, B, C or D to complete the following sentences.(1.5 pts) 26. I extend my sincere_____ to the family and friends of John Miller, who has suddenly left us at the age of 54. A. appreciation B. description C. condolences D. charges 27. Hotel employees are reminded to be_____ and courteous, especially to first-time guests. A. friend B. friends C. friendly D. friendship 28. The government issued a warning to local companies that all waste must be disposed of___or they will face heavy fines. A. corrects B. correcting C. correction D. correctly 29. Golf Weekly is a newly published magazine that caters_____ to experienced and inexperienced golfers who are just learning to play the game. A. both B. neither C. either D. so 30. We are seeking an _____ to represent us in talks with our Japanese clients. A. interpreta B. interpreter C. interpreting D. interpretation 31. We believe that_____ recent changes in state laws, the majority of students will get a job after graduating the university. A. due to B. whereas C. otherwise D. instead of 32. _____ in universities around the nation has more than tripled compared to this time last year. A. Enroll B. Enrolls C. Enrolling D. Enrollment 33. _____ Mr. Brown retires, he will receive an annual pension of more than fifty thousand dollars from the government. A. Often B. Once C. Whoever D. Sometimes 34. _____ Mr. Parker’s promotion became official, many of his colleagues have approached him to congratulate him. A. Despite B. Still C. Since D. During 35. John Clarke, who is in the prime of his career, has been ranked_____ the top 10 players in tennis history by Sports Daily. A. at B. into C. among D. from 36. He thought the talk was fascinating. His friend, _____, fell asleep halfway through it. A. although B. nevertheless C. so as D. in spite of 37. She ____ modern art. She visits all the local exhibitions. A. looks down on B. goes in for C. fixes up with D. comes up against 38. I didn’t see anyone but I felt as though I ____. A. have been watched B. was being watched C. being watched D. am watched 39. After going to the zoo, the mall and the movies, Cassie was sick of ____ to entertain her nieces. A. pushing the envelope B. turning the other cheek C. bending over backwards D. going against the grain 40. Helen: “This is your first trip abroad, isn’t it?” Peter: “____.” A. No, I haven’t been there before B. No, it’s expensive C. Yes, it sounds great D. Yes, so I’m looking forward to it

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