In the figure below, ABC is an isosceles triangle (AB = BC) with altitude BE = h. D is a point on AC, r1 is the exradius of the triangle ABD corresponding to AD and r2 is the exradius of the triangle DBC corresponding to BC. Prove that r2 - r1 = h.
BD is called an interior
cevian of triangle ABC.
See also:
Typography of problem 1375.