Question

The area of a small rectangular plot is $84m^2$ . If the difference between its length and the breadth is $5m$; find its perimeter.

Answer 1

Let $l$ and $b$ be the length and breadth of rectangular plot.

Area of rectangular plot $=84m^2$

$\Rightarrow l\times b=84.....\left(1\right)$

Also,

$l-b=5$

$\Rightarrow l=5+b$

Substituting the value of $l$ in equation $4\left(1\right)$

$(5+b)\times b=84$

$b^2+5b-84=0$

$(b+12)(b-7)=0$

$\because b\ne -ve$

$\therefore b-7=0\Rightarrow b=7m$

$\therefore l=5+b=5+7=12m$

Therefore,

Perimeter of plot $=2(l+b)=2\times (12+7)=38m$