Thread: Prove Theorem

This forum has been slowing down of late, so to increase dicussion I will provide a challenge. The challenge is the following:

Prove Heron's formula for the area of a triangle with sides , , and and semiperimeter .

Note: Heron's formula for the area of a triangle is

Wikipedia has two proofs of the theorem, one using trigonometry and the other using Pythagoras’s theorem.

• http://en.wikipedia.org/wiki/Heron%27s_Formula