The area of the blue circular sector is exactly half that of the equilateral red trangle .
How much larger is compared to the green disc inscribed in the circular sector ?
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Let r be the radius of the green inner circle and d the distance between A and the inner circle's center.
Let A b l u e be the area of the circular sector, A r e d the area of the triangle △ A B C and A g r e e n the area of the inner circle.
We can write sin ( ∠ C A B ) = sin ( 6 π ) = d r ⇒ d = 2 r .
Since A b l u e = 6 π ( d + r ) 2 = 2 A r e d , then A r e d = 3 π ( d + r ) 2 = 3 π ( 3 r ) 2 = 3 π r 2 = 3 ∗ A g r e e n ⇒ A g r e e n A r e d = 3