Problem 283: Circular Sector 90 degrees, Semicircle, Circle
inscribed, Radius.
The figure shows a circular sector AOB of 90 degrees with radius R. OB is the diameter of semicircle C. In the region between the sector AOB and the semicircle C, a circle D is inscribed, tangent to OA, arc AB, and the semicircle C. If r is the radius of the circle D, prove that r = R / 4.

Recent Additions
