Luann has a platter made out of a square, with semicircles of diameter 10 inches on each edge, as shown. What is the side length of the smallest square that can contain the platter, in inches?

Luann has a platter made out of a square, with semicircles of diameter 10 inches on each edge, as shown. What is the side length of the smallest square that can contain the platter, in inches?