Question

The perimeter of a rectangle is 40cm. If the length is 3times the breadth, calculate the area of the rectangle

Answer 1

Explanation:

Let
`l` be length,
`b` be breadth.

`l=3b`
`(a)` (the length is 3times the breadth)

`2l+2b=40`
`(b)` (perimeter is 40)

Now we must solve these to find
`l` and
`b`:

Substitute
`(a)` into
`(b)` :

`2(3b)+2b=40`

`6b+2b=40`

`8b=40`

`b=5cm`

Substitute
`b=5` into
`(a)`:

`l=3* 5=15cm`

Find area:

`A=lb=15 * 3=45cm^2`