Question

The perimeter of the rectangle is$200cm$. Its length is three times its breadth. find its length and breadth.

Answer 1

Step 1 : Find the relation between length & breadth as given in question.

Let the breadth = $b$

So, the length will be $=$ $3\times b=3b$

Step 2 : Now put the values in the formula of the perimeter to calculate them.

$\because$ The perimeter of the rectangle $=2\left(\mathrm{length}+\mathrm{breadth}\right)$

$\therefore$The perimeter of the given rectangle$=2\left(b+3b\right)$

Given that the perimeter of the rectangle is $200cm$

$\therefore$$2\left(b+3b\right)=200$

$\begin{array}{rcl}& \Rightarrow & 2\left(4b\right)=200\\ & \Rightarrow & 8b=200\\ & \Rightarrow & b=\frac{200}{8}\\ & \Rightarrow & b=25cm\end{array}$

Then, the length will be $3\times 25=75cm$

Hence , length = $75cm$& breadth = $25cm$ .