1.圆的半径是5cm,弦AB所对的圆周角为90°,则AB=______.2.圆O的半径为8,弦AB=8,则劣弧AB的度数等于( )A.30° B.120° C.150° D.60°

问题描述:

1.圆的半径是5cm,弦AB所对的圆周角为90°,则AB=______.
2.圆O的半径为8,弦AB=8,则劣弧AB的度数等于( )
A.30° B.120° C.150° D.60°

5倍根号2
D