Let x be the width and y be the height of a norman window. Thus, the semi-circle has radius x/2. We must maximize the area of the window, A = xy + pi/2(x/2)^2. The perimeter of the window is 20 = 2y + x + pi(x/2), and so y = __________________ - x/2 - (pi x)/__________________________.

Help filling the blanks? I assume I have to solve it a certain way, but I have no idea. Thanks.

Question

Let x be the width and y be the height of a norman window. Thus, the semi-circle has radius x/2. We must maximize the area of the window, A = xy + pi/2(x/2)^2. The perimeter of the window is 20 = 2y + x + pi(x/2), and so y = __________________ - x/2 - (pi x)/__________________________. 

Help filling the blanks? I assume I have to solve it a certain way, but I have no idea. Thanks.