# Two Moons and Right-angle Triangle

Geometry Level 4

$$AB$$ is the diameter of the semicircle. $$C$$ is a point on the circumference.$$O$$ is the center if the semicircle.

If the radius of the semicircle is 5,$$\angle COA=60^\circ$$. Find the sum of the area of the region $$R$$ and $$S$$. note region R and S is not the semicircle with the diameter AC and BC

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