Question 1
$100+\frac{\pi r^{2}}{2}=(2r)^{2}$
$200+\pi r^{2} = 8r^{2}$
$r=\sqrt{\frac{200}{8-\pi}}=10\sqrt{\frac{2}{8-\pi}}$
$100+\frac{\pi r^{2}}{2}=(2r)^{2}$
$200+\pi r^{2} = 8r^{2}$
$r=\sqrt{\frac{200}{8-\pi}}=10\sqrt{\frac{2}{8-\pi}}$