Question

在直角三角形ABC中,角ACB=90,CD垂直于AB,角A=30,求证BD=1/4AB

Answer 1

设BC = 1 AB = 2 (30度对边= 斜边一半)

又因为：在Rt△ABC中,∠ACB=90,CD⊥AB,∠A=30,

所以,∠DCB = ∠A = 30,

BD = 1/2 (30度对边= 斜边一半)

BD =1/4AB