Right-Angled Triangles - Click the Green Flag to start. Change the Short-a & Medium-b sliders to change Triangle drawn. Hit (Proof) to see an animation of Pythagoras' elegant proof by re-arrangement of the Theorem bearing his name. Hit Space (or the Green Flag) to switch back to drawing right-angled triangles.
Created by @gregatku for use in Coding Classes for Kids Unlimited. When drawing the last long side (c) it uses Pythagoras' Theorerm to calculate its length, and the asin (or arcsin) function to get the Angle opposite the short side (a). The Sine of a non-right angle in a right-angled triangle is the length of the side opposite the Angle divided by the length of the long side. So we want asin(a/c), but because we were pointing right, we have to turn 180 - asin(a/c) to form it.
