如图,正方形ABCD中,点E、F分别在BC、CD上,△AEF是等边三角形,连接AC交EF于G,下列结论:①BE=DF,②∠DAF=15°,③AC垂直平分EF,④S△CEF=2S△ABE,其中正确的结论有( )
A:1个
B:2个
C:3个
D:4个
一个多边形的内角和等于外角和的3倍,则多边形的边数是____
There was something wrong with the line. We couldn't _______ each other clearly.