LUNE OF HIPPOCRATES
The Lune of Hippocrates is the upper shaded area. It has the same
area as the lower shaded triangle.
In geometry,
the lune of Hippocrates, named after Hippocrates of Chios, is a lune bounded
by arcs of circles, one of which passes through the center of the other and has
half the area of the other. Equivalently, it is a non-convex plane region bounded by one
180-degree circular arc and one 90-degree circular arc.