The length of a rectangle is 12 in. and the perimeter is 56 in. find the width of the rectangle

The perimeter p of the rectangle with length l and width w is:

p = 2l + 2w

that is, two times its length and two times its width, lets solve for the width w and substitute known dа ta:

p = 2l + 2w

2w = p - 2l

w = (p - 2l) / 2

w = (56 - (2*12)) / 2

w = (56 - 24) / 2

w = 32/2

w = 16

therefore the width of the rectangle is 16 in