Illustration of a circle used to prove "Any angle inscribed in a segment less than a semicircle is an…

Illustration of a circle with a right angle inscribed in a semicircle.

Illustrations of a circle with segment, semicircle, sector, quadrant, and central angles drawn.

Circular design made by rotating circles about a fixed point. The radii of the smaller circles is equal…

Circular design made by rotating circles about a fixed point. The radii of the smaller circles is equal…

Illustration of a how to construct a square equivalent to a given parallelogram.

"The outer edge is a semicircle, with center at 0, and is divided into 360 parts. Each division is one-half…