Question 1035127
If you draw the diagram, you can sketch in the radius 12 from the center of the circle to the corner of the rectangle.  Using the Pythagorean Theorem, you can find half the base of the rectangle to be
{{{sqrt(144-h^2)}}}
The whole base of it is twice that.  The area of the rectangle is h times THAT.  Thus
{{{A(h) = 2h*sqrt(144-h^2)}}}