Question 918440
The problem description is somewhat ambiguous.  Width of the window is 7.500 feet; but is THE semicircle attached to a width or is it attached to a length?    Any figure or diagram included in your book or page might help tell you this nonverbally.


I can explain generally.


x and y are the dimensions of the rectangle portion of the window.  You know perimeter of the window p and one of the diensions, either x or y;
but you do not know A area of the window.


p=36.9000
A is unknown
either x or y is known but not both.


Either x or y serves as diameter of the semicricle, but only one of those dimensions; NOT both, and not both at the same time.


If the semicircle has diameter of y, then {{{highlight_green(A=pi*(y/2)^2+xy)}}}, and {{{highlight_green(p=(1/2)2pi*(y/2)+2x+y)}}}.


Nothing more specific without the exact and complete problem description.