$\frac{\pi(\pi-2)}{2}$

1

$\frac{\pi(\pi+2)}{2}$

$\frac{\pi}{4}$

10

6

4

3

$\frac{24}{5} 2^{\frac{1}{4}}$

$\frac{5}{24} 2^{\frac{3}{4}}$

$\frac{32}{5} 2^{\frac{1}{4}}$

$\frac{5}{12} 2^{\frac{3}{4}}$

$\frac{128}{105}$

$\frac{16}{35}$

$\frac{256}{105}$

$\frac{32}{35}$