L = π(r√2/2)²/2­ - (πr²/4 - r²/2) = r²/2 = T[br][code]https://latex.codecogs.com/svg.image?L=\pi\left(\frac{\sqrt{2}}{2}r\right)^2\frac{1}{2}-\left(\pi\frac{r^2}{4}-\frac{r^2}{2}\right)=\frac{r^2}{2}=T[/code][br][code]L=\pi\left(\frac{\sqrt{2}}{2}r\right)^2\frac{1}{2}-\left(\pi\frac{r^2}{4}-\frac{r^2}{2}\right)=\frac{r^2}{2}=T[/code][br]