2n+2(n-4)=56
2n+2n-8=56
4n-8=56
4n=64
n=16
1st side is 16
2nd side is 12
Answer: 5 feet
Step-by-step explanation: A rectangle is a quadrilateral with 4 sides. The opposite sides are parallel and have the same length.
Top and bottom of the window are opposite, so they have the same measure of 3 feet.
One length of the window is 5 feet. Since the last side is opposite to the length of the window, it has the same length, i.e., its value is 5 feet.
5x - 5 = x + 11
5x = x + 16
4x = 16
x = 4