39??

40 Peter is going to listen to music after work.

41 It's funny to walk in the rain.

42 He spent five minutes going to school.

43 Hung asked Nam  to close the book.

44 His sister is an excellent cook.

45 We used to live in the country when we were young.

cho tam giác ABC vuông tại A có đường cao AH và đường trung tuyến AM, kẻ HE vuông góc AB tại E, HF vuông góc AC tại F .

Chứng minh EF=AH
góc BAH= góc MAC 

EF=AM