In the triangle ABC, AB is equal to AC, angle a is equal to 120 degrees, BC is equal to 6cm, the vertical bisector angle BC of AB is in M, which is called AB in E, the vertical bisector angle BC of AC is in N, and the angle AC is in flight. To prove: BM is equal to Mn, and NC is equal to Mn

In the triangle ABC, AB is equal to AC, angle a is equal to 120 degrees, BC is equal to 6cm, the vertical bisector angle BC of AB is in M, which is called AB in E, the vertical bisector angle BC of AC is in N, and the angle AC is in flight. To prove: BM is equal to Mn, and NC is equal to Mn


Prove: ab equals AC, angle a equals 120 degrees, so angle B = angle c = 30 degrees
So the angle amn = angle anm = 60 degrees, so amn is an equilateral triangle, BM = am = Mn = an = NC