Question

The perimeter of a square is 20 ft. If you increase the length of the square by 2 feet and decrease the width by 1 foot, what is the area, in square feet, of the new figure

Answer 1

All 4 sides of a square are the same length.
If the perimeter of the square is 20-ft, then each side is 20-ft/4 = 5 ft.

If you increase the length of the square by 2-ft, then its new length is 5+2 = 7-ft.
 
If you decrease the width of the square by 1-ft, then its new width is 5-1 = 4-ft.

The area of the new figure is (length) x (width) = (7-ft x 4-ft) = 28 square feet.

Answer 2

The square before the transformation would have side lengths of 5 since 5*4=20
so increasing the length and decreasing the width would make the square a rectangle with dimensions 7×4.
a=LW
a=(7)(4)
=28ft²