The picture is of a rectangle whose base is greater than its height. A circle is drawn in the rectangle, which is tangent to the top, left, and bottom edges. the diagonal from the bottom left corner to the top right corner meets the circle in points E and F. Express the distance EF in terms of the base and height.

http://i41.tinypic.com/2h6eh03.jpg

Not sure how to even start this off other than r=h/2