In square , one of the vertices of square touches at and and are tangent to the two congruent circles at and respectively and the radius of each circle is half the side of the square .
Let be the area of the pink shaded regions.
Find .
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Using the diagram above A C = 2 a = 2 x + x + 2 x + 2 x ⟹
4 a = ( 6 + 3 2 ) x ⟹ x = 6 + 3 2 4 a = 3 2 ( 2 + 1 ) 4 a = 3 2 2 ( 2 − 1 ) a
= 3 4 − 2 2 a and C Q = 2 x + 2 x = 2 2 2 + 2 x = 2 2 2 ( 2 + 1 ) x =
2 2 + 1 x = ( 2 2 + 1 ) ( 3 4 − 2 2 ) a = 3 2 a
△ F C G is a right isosceles triangle ⟹ F Q ≅ Q G ⟹ △ F Q C ≅ △ C Q G ⟹
A △ F C G = 2 A △ F Q C = 2 ( 2 1 ( C Q ) 2 ) = 9 2 a 2
and A △ A E H = 2 A △ A E P = 2 ( 2 1 ) ( 2 x ) 2 = 2 x 2 = 9 2 ( 4 − 2 2 ) 2 a 2 =
9 2 ( 2 4 − 1 6 2 ) a 2
Let A s = A △ F C G + A △ A E H = 9 2 ( 2 5 − 1 6 2 ) a 2
The area of circle A c = π r 2 = π ( 2 x ) 2 = 9 π ( 2 − 2 ) 2 a 2 = 9 2 π ( 3 − 2 2 ) a 2
Let A ∗ = A s + A c = 9 2 ( 2 5 − 1 6 2 + ( 3 − 2 2 ) π ) a 2 ⟹
A T = a 2 − A ∗ = 9 3 2 2 − 4 1 − 2 ( 3 − 2 2 ) π a 2 ⟹
A A B C D A T = 9 3 2 2 − 4 1 − 2 ( 3 − 2 2 ) π ≈ 0 . 3 5 2 9 7 8 8 6 9 6 7 .