Question

已知:AD,BE是锐角三角形ABC的高,A'D',B'E'是锐角三角形A&apo

Answer 1

DB/AD=D'B'/A'D',∠ADB=∠A'D'B',所以三角形ADB和三角形A'D'B'相似,则∠BAD=∠B'A'D' 又因为∠C=∠C',∠ADC=∠A'D'C'所以三角形ADC和三角形A'D'C'相似,则∠DAC=∠D'A'C',综上,∠BAC=∠B'A'C',又∠C=∠C',三角形ABC和三角形A'B'C'相似,所以AD*B'E'=A'D'*BE