I personally love the idea of Proofs Without Words! I like how simple, elegant and creative they can be. So here is another one for all you proof enthusiasts. Link
In this proof, we see that = .
is cut into multiple similar triangles with a ratio r. is . For the purposes of this proof, let the point where line meets be .
because they're vertical angles. since they are both right angles. Thus by Similarity. Since , .
Tinkering with our ratios, we get