A Norman Window Has the Shape of a Rectangle Surmounted $$A ( x ) = \frac { 160 x - 4 x ^ { 2 } - \pi x ^ { 2 } } { 8 }$$

Multiple Choice

A Norman window has the shape of a rectangle surmounted by a semicircle as in the figure below.If the perimeter of the window is 40 ft,express the area,A,as a function of the width,x,of the window.

A) $$A ( x ) = \frac { 160 x - 4 x ^ { 2 } - \pi x ^ { 2 } } { 8 }$$
B) $$A ( x ) = \frac { 80 x - x ^ { 2 } } { 2 }$$
C) $A ( x ) = \frac { 80 x - 2 x ^ { 2 } - \pi x ^ { 2 } } { 4 }$
D) $A ( x ) = \frac { 80 x + ( 2 - \pi ) x ^ { 2 } } { 4 }$
E) $A ( x ) = \frac { 160 x - 4 x ^ { 2 } - \pi x ^ { 2 } } { 2 }$