Question

已知⊙O的半径为6cm,一条弦AB=根号6 cm,则弦AB所对的圆周角是

Answer 1

如图所示：

设圆心角为∠AOB

圆周角为∠ACB

则∠AOB=2∠ACB=2∠AOD

∠ACB=∠AOD

SIN∠AOD=((根号6)/2)/6

=根号6/12

∠ACB=∠AOD=arsin(根号6/12)