The figure shows a quadrilateral ABCD,
E, F, G, and H are the midpoints of the sides, lines EG and FH
meet at M. If a, b, c, d and m are the perpendiculars
drawn from A, B, C, D, and M to an exterior line A'D', respectively,
prove that:
4m = a + b + c + d.
View or post a solution.
