We have been given diagram of a wooden window. We are asked to find the amount of wood that carpenter needs to build the frame.
The amount of wood needed for the window frame will be equal to area of window frame.
We can see that upper part of window is semicircle. The area of the semicircle is half the area of the circle.
, where,
R = Outer radius,
r = Inner radius.




The area of lower part of frame will be area of 3 rectangles. 2 same rectangles with length 48 inches and width 1 inch. One rectangle with length 10 inches (12-2) and width 1 inch.




Therefore, option A is the correct choice.