Check the picture below.
so we have a rectangle with two circles, the rectangle is a 21x10.5 and the circle's have a radius of 5.25, so let's get the area of the two circles and subtract it from the whole area of the containing rectangle.
[tex]\stackrel{\textit{\Large Areas}}{\stackrel{rectangle}{(21)(10.5)}~~ - ~~\stackrel{two~circles}{2[\pi (5.25)^2]}}\implies 220.5~~ - ~~55.125\pi ~~\approx~~47.32[/tex]
