已知如图,在△ABC中,AB=AC,点M,N在AC上,且MB=MN,∠ABN=∠MBC,求∠NBC的度数

∠用"代替
MN=MB
"MBN="MNB
"MNB="A + "ABN
"MBN="A + "ABN
∠ABN=∠MBC
"ABC="ABN + "MBN +"MBC = 3"ABN + "A
AB=AC
"ABC = "C
3角型内角和为180
"A + "ABC + "C = "A + 2"ABC = "A + 2*(3"ABN + "A) = 6"ABN + 3"A =180
2"ABN + "A = 60
"A = "MNB - "ABN
2"ABN + "MNB - "ABN = "ABN + "MNB = "MBC + "MBN = 60 = ∠NBC
不会打因为所以.只好这样啦~
应该这样吧~如果有更简单的方法记得打出来啊~

悬赏0，问的还是这么没意义的题，楼主您可以问下你的几何老师哈，要不学费岂不白交了