题目内容
如图,AB为⊙O的直径,点C在⊙O上,若∠B=60°,则∠A等于
A.80° B.50° C.40° D.30°
D
解析:略
如图,AB为⊙O的直甲径,PD切⊙O于点C,交AB的延长线于D,且CO=CD,则∠PCA=
A.60°
B.65°
C.67.5°
D.75°