In the triangle ABC, ab = AC, D is the point on AB, e is the point on the extension line of AC, and BD = CE, de intersects BC in flight. The proof: DF = Fe

In the triangle ABC, ab = AC, D is the point on AB, e is the point on the extension line of AC, and BD = CE, de intersects BC in flight. The proof: DF = Fe

When BC is extended and eg / AB intersects g through e, angle EGC is equal to angle B, because AB = AC, so angle B = angle c, angle c = angle ECG, so EC = eg, so triangle BDF is equal to triangle GEF, so DF = Fe