It is known that D and E are the points on the sides BC and AC of the equilateral triangle ABC, BD = CE, connect be and ad, intersect point F, and prove the angle AFE = 60 degrees

It is known that D and E are the points on the sides BC and AC of the equilateral triangle ABC, BD = CE, connect be and ad, intersect point F, and prove the angle AFE = 60 degrees

Proof: because the equilateral triangle ABC, BD = CE, ∠ ABC = ∠ ACB, △ abd ≡ BCE; ∠ BDA = ∠ BEC, ∠ FBD = ∠ bad, ∵ sum of internal angles of triangle = 180 °, ∠ BFD = ∠ abd, ∵ BDF is similar to △ BEC, ∠ BFD = ∠ BCE = 60 ° = ∠ AFE (equal to vertex angle)