Below is an image of a square, 7 cm to a side, with four quarter-circles inscribed into it as showm.
Find the area of the shaded region in the center.
(In reply to
re: First steps? by levik)
None taken. However, the fact that it appears that there should be an elegant solution does not mean that there is one. There are some inocuous looking problems out there that don't even have any known closed-form solution at all. Personally, I'll settle for a working solution first, then look for a more elegant solution if one suggests itself.
BTW,you could probably demonstrate a more elegant solution using calculus, but I wanted to keep it at the high-school geometry level.