Find the perimeter of a rectangle whose length is 6 more than its width (width = W).

Correct answer: 4W + 12. Length = W + 6, so the perimeter = 2(W + 6 + W) = 4W + 12.

Background: The perimeter of a rectangle is 2 × (length + width).

• 4P + 12: P is not the width in this problem.
• 4A + 12: A is not the width in this problem.
• 4L + 12: L is the length, not the width.

Did you know? Name the smaller side W and write the other in terms of W.

Memory trick: 2(2W + 6) = 4W + 12.