[quote="Bunuel"]

ABC is an equilateral triangle of area 3, and arc DE is centered at C. If E is the midpoint of AC, what is the area of the shaded region?
A. \(3-\frac{\sqrt{3}\pi}{2}\)
B. \(3-\frac{\pi}{\sqrt{3}}\)
C. \(3-\frac{\pi}{2}\)
D. \(3-\frac{\pi}{2\sqrt{3}}\)
E. \(3-\frac{\pi}{6}\)
We should know two concepts before attempting this question:
1) Formula for area of n equilateral triangle (\(\sqrt{3} /4 * Side^2 \))
2) Formula for area of a sector (\(\frac{area of sector }{ area of circle} = \frac{angle of sector }{ 360}\))
So, here Area of equ triangle = 3
=> \(\sqrt{3} /4 * a^2 = 3 \)
=> \(a^2 = 4\sqrt{3} \)
Area of sector / Area of circle = Angle of sector / 360
=\({\pi} r^2\)*60 /360 =\( {\pi} a^2/4 * 1/6\).... it is given that the E is midpoint of the side AC.. so r = a / 2
=\( {\pi}a^2/24\)
=\( {\pi}4\sqrt{3} /24\)
=\( {\pi}/2\sqrt{3}\)
Therefore, area of shaded portion of equilateral triangle = \(3-\frac{\pi}{2\sqrt{3}}\)... i.e D