The perimeter of a rectangle is found by multiplying the length by 2 and then adding that to the width multiplied by 2.
The length is 7, multiplied by 2 = 7x2 = 14.
Subtract that from the total perimeter:
42 - 14 = 28
The length of the 2 widths is equal to 28, to find the length of 1 width, divide that by 2:
Width = 28 / 2 = 14
The width is 14 feet.
