2*71.5-124=19
The overlap region is 19 units wide.
Can you use calculus?. Probably not?. We can do it without, but calc would be cool to set up an integral.
Center the leftmost circle at (71.5,0), then its equation is \(\displaystyle y=\sqrt{-x^{2}+143x}\)
The circles intersect at x=133.5
So, we double the integral because we integrate from the intersection to the edge of the circle. The other half lies in the other circle. But due to symmetry we can just double it.
\(\displaystyle 2\int_{133.5}^{143}\sqrt{-x^{2}+143x}dx=457.45 \;\ units\)