Answer
$=\frac{\pi}{5}$
Work Step by Step
$r=2sin5\theta$
Area enclosed by one loop is
$A=\frac{1}{2}\int_{0}^{\pi/5}4sin^{2}(5\theta)d \theta$
$=2\int_{0}^{\pi/5}( {\frac{1}{2}-\frac{1}{2}cos(10\theta)}) d \theta$
$=\frac{\pi}{5}$