$\displaystyle \frac{3}{4}\pi$\displaystyle \frac{3}{4}\pi

$\displaystyle \frac{1}{2}\pi$\displaystyle \frac{1}{2}\pi

$\displaystyle \frac{3}{4}\pi +6$\displaystyle \frac{3}{4}\pi +6

$\displaystyle \frac{1}{2}\pi+6$\displaystyle \frac{1}{2}\pi+6