The goal of this page is to prove the property found on the page above (https://www.geogebra.org/m/A2NGCM3K).[br][br]Use the scroll bar to unfold the idea behind the proof (or rather, one of the proofs. The law of sines provides a much shorter proof).[br]

pause.[br][br]why does [math]BH_a=BH[/math]? [br]once you have answered that question you may continue: