So remember that the perimeter is the sum of all the sides, and a rectangle is a quadrilateral, or four-sided polygon. Since we know that 2 of the sides is 91 yds and the perimeter is 338 yds, we can solve for the width. Our equation will look like this (let w = width):

Firstly, do the multiplications:

Next, subtract 182 on both sides:

Next, divide both sides by 2, and your answer will be w = 78 yds.