In an equilateral triangle ABC, points M, N, K are the midpoints of the sides AB, BC, CA, respectively. Prove that triangle MNK is equilateral
May 31, 2020 | Education
| Consider the triangles AMK, MBN, and NCK.
∠A = ∠B = ∠C (by the property of an equilateral triangle).
AM = MB = BN = NC = CK = KA (by the condition of the problem).
Therefore, the triangles AMK, MBN and NCK are equal (by the first sign).
It follows that MN = MK = KM => the triangle MNK is equilateral (by definition).
