Question

The length of a rectangle is twice its width.

If the perimeter of the rectangle is 30 cm, find its length and width.

Answer 1

width - 5cm

length - 10cm

Explanation:

Let's define the variable w as the width of the rectangle. The length of the rectangle would be 2w as given by the problem. A form of the perimeter of a rectangle formula is:

P = 2(l + w)

Where P is the perimeter, l is the length, and w is the width. We substitute our length, width, and perimeter to get:

30 = 2(2w + w)

You can simplify to get:

30 = 2(3w)

and divide by 6 on both sides to isolate w:

w = 5cm - the width is 5 cm

The length is twice the width, and 2 x 5 is 10, so 10cm is the length.