2012 AMC 12A Problem 14
Problem 14 of 25IntermediateGeometry
The closed curve in the figure is made up of congruent circular arcs each of length where each of the centers of the corresponding circles is among the vertices of a regular hexagon of side What is the area enclosed by the curve?

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Solution
Each arc has length on a unit circle, so it is a sector. The nine equal sectors can be reassembled so that the enclosed region equals the regular hexagon of side plus one full circle of radius
A regular hexagon of side splits into equilateral triangles of side so its area is
Adding the unit circle’s area gives
Thus, the correct answer is E.