has side length . The quarter-circle sectors and are drawn, along with diagonal . If the area of the shaded region is , where are all integers with not divisible by the square of any prime and , find .
Square
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Reference this diagram .
I will refer to the area obtained by removing the triangle portion of a sector as a segment . Note that the desired area is the area of the segment of the large quarter circle containing the desired area, minus the red and green regions. The red region is a segment of a sector of measure 60 degrees (since E B = A B = A E which implies that △ E A B is equilateral), and the green region is a sector of measure 15 degrees. The larger segment is a portion of a sector of 90 degrees.
Area of the Red Region
The area of the red region is 6 1 ( π ) − 4 3 . (A 60-degree sector with radius 1 minus the area of an equilateral triangle with radius 1.)
Area of the Green Region
The area of the green region is 2 4 1 ( π ) . (A 15-degree sector with radius 1.)
Area of the Quarter-Circle Segment
The area of the quarter circle segment is 4 1 ( π ) − 2 1 . (A 90-degree sector with radius 1 minus the area of an isosceles right triangle with leg length 1.)
Area of the Desired Region
This is equal to the area of the quarter-circle segment minus the sum of the areas of the red region and the blue region.
4 1 ( π ) − 2 1 − ( 6 1 ( π ) − 4 3 + 2 4 1 ( π ) )
I'll save you the simplification and tell you that the desired answer comes out to 2 4 π − 1 2 + 6 3 , from which the desired answer is 1 2 + ( − 1 2 ) 2 + 6 2 + 3 2 + 2 4 2 = 7 6 6 .