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°
答
5倍根号2
D