Your turn
MathsKS3
Rectangle Perimeter Brain Teaser
A rectangle has a perimeter of 36cm. Its length is twice its width. What are the rectangle's dimensions?
Show the worked solution
What's the puzzle?
A rectangle has a perimeter of 36cm. Its length is twice its width. What are the rectangle's dimensions?
How do you work it out?
Let the width be w and the length be 2w. The perimeter of a rectangle is twice the sum of its length and width, so 2(w + 2w) = 36, which simplifies to 6w = 36 and w = 6.
The width is 6cm and the length is 12cm. Checking: 2 × (6 + 12) = 36cm, which matches the perimeter given.
Last updated: