Draw the sine squared of an angle

Given an angle α, how to draw a segment of length sin²α or cos²α. The procedure can also be done in reverse order: from segment length to angle.

Notes: *(CH)² = (AH)(HB), regardless of the length of the hypotenuse: [url]http://www.geogebratube.org/material/show/id/31122 [/url] *To apply the trigonometric relationships here to an arbitrary right triangle, scale them by the length of the hypotenuse.