Question

The length of a rectangular billboard is 9 meters more than the width. If the perimeter is 42 meters find the dimensions.

Answer 1

Given, the perimeter of the rectangular billboard, P=42 m.

The length of the rectangular billboard is 9 m more than the width.

Let l be the length and w be the width of the rectangular billboard.

Then, the length can be expressed as,

`l=9+w`

The perimeter of a rectangle can be expressed as,

`P=2(l+w)`

Now, put l=9+w and P=42 m in the above equation to find w.

`\begin{gathered} 42=2(9+w+w) \\ (42)/(2)=9+2w \\ 21=9+2w \\ 21-9=2w \\ 12=2w \\ (12)/(2)=w \\ 6m=w \end{gathered}`

Hence, the length is,

`\begin{gathered} l=9+w \\ l=9+6 \\ l=15\text{ m} \end{gathered}`

Therefore, the length of the rectangular billboard is 15 m and the width of the rectangular billboard is 6 m.