Answer:
both the Width and Length of the base are equal to 55.125 ft
Step-by-step explanation:
Based on the information provided by the question we know that the width is equal to the length, therefore the base of the Washington Monument is a Square. The Perimeter of a Square is equal to the addition of all four sides (length and width).
Therefore since we know that the perimeter is 220.5 and all 4 sides are equal then we can divide the perimeter by 4 in order to know the size of the the sides
220.5 / 4 = 55.125 ft
Finally we can see that both the Width and Length of the base are equal to 55.125 ft