The perimeter of a rectangle is 100 yd. if its width is four times its length, what is the area?

Length = l

Width = w

Perimeter = p = 100

Perimeter of rectangle = 2 (l+w)

100 = 2 (4w + w)

100 = 2 (5w)

100 = 10w

100/10 = w

10 = w

w = 10

Area of rectangle = length * width

a = l*w

a = 4w*w

a = 4w^2 ... (1)

Put the value of w in (1)

a = 4 (10) ^2

a = 4 (100)

a = 400 yd^2