Hello,
I have search in my memory : (not sure)
[tex]A= \pi* \dfrac{25}{2}+ 2*\int\limits^{5}_{ \frac{5}{2}} { \int\limits^{\sqrt{25-(x-5)^2}}_{\sqrt{25-x^2}} \, dx } \, dy \\
= \int\limits^{\frac{\pi}{3}}}_{- \frac{\pi}{3}} \int\limits^{10\ cos(\theta)} _5 {\rho} \, \ d\rho \ d\theta
[/tex]
But we can make easier (see picture)
