题目内容
如图,AB为⊙O的直径,弦CD⊥AB于E,已知CD=12,则⊙O的直径为
A.8
B.10
C.16
D.20
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°