user-avatar
datvyvp
2 năm trước
cho hcn abcd (ab>bc) có 2 đường chéo ccắt nhau tại O. đường thẳng qua D vuông góc với DB cắt đường thẳng bc tại E. a) chứng minh tam giác BDE và tam giác BCD đồng dạng; BC mũ 2 = BC*BE b) kẽ CH vuông góc với DE (H thuộc DE ), gọi I là giao điểm của OE và HC.Chứng minh I là trung điểm của CH c)CHỨNG MINH BA ĐƯỜNG THẲNG OE, BH,CD đồng quy
Thích Trả lời Chia sẻ

Các câu hỏi liên quan

D. WRITING (2 pts) I. Choose one sentences that has the same meaning as the root one: (1 pts) 31. Unless we protect the envirnment, our life will be badly affected. A. If we protect the envirnment, our life will be badly affected. B. If we don’t protect the envirnment, our life will be badly affected. C. If we don’t protect the envirnment, our life won’t be badly affected. D. If our life is badly affected, we will protect the envirnment. 32. They are building a new bridge over the river. A. A new bridge is building over the river. B. A new bridge is being built over the river. C. A new bridge is going to build over the river. D. A new bridge is built over the river. 33. I used to go to the cinema on Sartudays. A. I usually went to the cinema on Sartudays. B. I got used to going to the cinema on Sartudays. C. I didn’t go to the cinema on Sartudays. D. I usually go to the cinema on Sartudays. 34. “Do you know Trang’s address?” he asked me. A. He asked me for Trang’s address. B. He asked me if someone knew Trang’s address. C. He asked me if I know Trang’s address. D. He asked me if I knew Trang’s address. 35. You feel unhealthy because you don’t take any exercise. A. If you took more exercise, you would feel healthier. B. If you take more exercise, you will feel healthier. C. If you were healthier, you would take more exercise. D. If you don’t take any exercise, you will feel unhealthier

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