The length of a rectangle is twice it's width. If it's perimeter is 54cm, find its length. Explain!
remember the formulas:
Area = length * width
Perimeter = 2 * length + 2 * width
therefore 54 = 2l + 2w and length is 2 * width or l = 2w
54 = 2* (2w) + 2w
54 = 4w + 2w
54 = 6w
54/6 = w
9 = w and
l = 2*9
l = 18