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下列命题中,正确命题的有( )个 ①一组对边平行且相等的四边形是平行四边形 ②一...
下列命题中,正确命题的有( )个
①一组对边平行且相等的四边形是平行四边形
②一组邻边相等的平行四边形是正方形
③对角线互相垂直且相等的四边形是菱形
④任何三角形都有外接圆,但不是所有的四边形都有外接圆.
A.1
B.2
C.3
D.4
考点分析:
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