D is a point on the side BC of triangle ABC, and the angle bad = angle C. try to prove that the square of AD / the square of AC = BD / BC?

D is a point on the side BC of triangle ABC, and the angle bad = angle C. try to prove that the square of AD / the square of AC = BD / BC?

∫ - abd = - C, ∫ B = - B ∫ abd ∫ CBA ∫ AD / AC = AB / BC = BD / AB ∫ AB ^ 2 = BD * BC ∫ ad ^ 2 / AC ^ 2 = AB ^ 2 / BC ^ 2 = BD * BC / BC ^ 2 = BD / BC area method ∫ - abd = - C, ∫ B = - B ∫ abd ∫ CBA ∫ s ∫ abd: △ SABC = BD ∶ CD = ad ^ 2 ∶ AC ^ 2