Question

A rectangle has a perimeter of 60 cm. It's length is 21 cm. What is its width (w)?

Answer 1

Okay so we know the length is 21. But with perimeter, we have two lengths. So 21+21 is 42. Then subtract 42 from 60, which is 18. Then, since we know there are two widths, divide 18 by 2. This gives you 9. 9cm

Answer 2

It’s width is 9cm.

We use the formula P = 2(l + w) in which the formula goes as:

w= p/2 - l= 60/2 - 21

= 9cm!