Question

The length of a rectangle is $2(x+6)$ cm, and its width is half of its length. What is its perimeter? [3 marks]

Answer 1

Let length (l) $=2(x+6)cm$
then width (b) $=\frac{1}{2}\times \text{length}$
$=\frac{1}{2}\times 2(x+6)cm=(x+6)cm$ [1 mark]

Now, perimeter of the rectangle
$=2(l+b)$
$=2\left[2\right(x+6)+(x+6\left)\right]cm$
$=2(2x+12+x+6)$
$=2(3x+18)$
$=(6x+36)cm$
Therefore, perimeter of the rectangle is $(6x+36)cm$. [2 marks]