Sum the circles

Circles intersects orthogonally at $A$ which means the angle between their tangents at $A$ is $90\degree$ . Tangent is always perpendicular to radius. So the angle between their radius $(OA$ and $PA)$ is also $90\degree$ .

Sum of the areas of two circles is $\pi OA^2 + \pi PA^2 = \pi(OA^2 + PA^2) = \pi OP^2 = \pi(\pi)^2 = \pi^3 = 31.006$