Problem 228.
Triangle, Midpoints, Exterior line, Perpendiculars

In a triangle ABC, D, E, and F are the
midpoints of the sides and A'C' is an exterior line. If a, b, c,
d, e, and f are the perpendiculars drawn from A, B, C, D, E, and
F to the line A'C', prove that: a + b + c = d + e + f.
View or post a solution.