user-avatar
kiengo93
2 năm trước
Cho tam giác ABC có 3 góc nhọn, vẽ các đường cao BD và CE. Gọi H,K theo thứ tự là hình chiếu của B,C trên đường thẳng ED. CMR:b S BEC + S BDC= S BHKC
Thích Trả lời Chia sẻ

Các câu hỏi liên quan

An adventure of The Johns’ Last week, while on vacation in Da Lat, The Johns had quite an adventure. One afternoon, they decided to paddle around Xuan Huong Lake in a canoe. After hiring the canoe, the family climbed in and paddled out to the middle of the lake. Unfortunately, dark clouds soon appeared and it began to rain.The wind started to blow and the rain became heavier. The canoe moved up and down the water. Unfortunately, Mary dropped her paddle and she leaned over and picked it up. Therefore, the canoe overturned and everyone fell into the deep and dangerous water. A boat appeared. Thanks to these people on the boat, This family was rescued. Questions: 1. Where did the Johns paddle last week? ->Last week, while on vacation in Da Lat, The Johns had quite an adventure. 2. What happened with the canoe? ->………………………………………………………………………………. 3. What was the weather like that afternoon? ->………………………………………………………………………………. 4. Was this family rescued? ->………………………………………………………………………………. 5. Who rescued The Johns? ->………………………………………………………………………………. 6. Were The Johns lucky after all? ->………………………………………………………………………………. 7. What would you do if you meet this situation like The Johns ? -> ……………………………………………………………………………...

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