挑战习题
1/5单选题
难度:

1.下列结沦中,错误的有(  )个
①Rt△ABC中,已知两边分别为3和4,则第三边的长为5;②三角形的三边分别为a、b、c,若,则∠A=90°;③若△ABC中,∠A:∠B:∠C=1:5:6,则这个三角形是一个直角三角形;④若成立,则M=4xy
A 0
B 1
C 2
D 3
提示1:
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正确答案:Qw==
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