挑战习题
1/5单选题
难度:

1.有下列结论:(1)平分弦的直径垂直于弦;(2)圆周角的度数等于圆心角的一半;(3)等弧所对的圆周角相等;(4)经过三点一定可以作一个圆;(5)三角形的外心到三边的距离相等;(6)垂直于半径的直线是圆的切线. 其中正确的个数为()
A 1个
B 2个
C 3个
D 4个
提示1:
IOagueaNruWeguW+hOWumueQhuWSjOWchuWRqOinkuWumueQhuaOqOaWre+8mw==
提示2:
IOagueaNruWIh+e6v+eahOWIpOWumuWumueQhu+8mw==
提示3:
IOagueaNruehruWumuWchueahOadoeS7tg==
正确答案:QQ==
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