Question

The formula P=2w + 2l is used to find the perimeter of arectangle, where w is the width and l is the length.Write a formula that can be used to find the length of arectangle. Show all your work.

Answer 1

The formula for the perimeter of a rectangle is given as;

`P=2w+2l`

To find the formula for the length of the rectangle in terms of the perimeter and the width, let make l the subject of formula.

Firstly subtract 2w from both sides of the formula;

`\begin{gathered} P-2w=2w-2w+2l \\ P-2w=2l \\ 2l=P-2w \end{gathered}`

Then divide both sides of the equation by 2;

`\begin{gathered} (2l)/(2)=(P-2w)/(2) \\ l=(P-2w)/(2) \end{gathered}`

Therefore, the formula that can be used to find the length of a

rectangle in terms of the perimeter and width is;

`l=(P-2w)/(2)`