Question

The side of a rectangular park are in the ratio of 4:3. If the area is 1728 m. Find its perimeter in the cost of fencing its at the rate of Rs 40 per m.

Answer 1

Let the common multiple be $x$.

Therefore the sides of the park be $4x$ and $3x$

Area of the park $=1728$sq.m

length $\times$ breadth $=1728$sq.m

$\Rightarrow 4x\times 3x=1728$

$12x^2=1728$

$x^2=\frac{1728}{12}=144$

$x=12$

hence,

length $=4\times 12=48$

breadth $=3\times 12=36$

perimeter $=2\times (l+b)$

perimeter $=2\times (48+36)$

$=2\times 84=168$m

Cost of fencing for $1$ metre is Rs$40$

Therefore,

Cost of fencing for $168$ m is $=168\times 40=$ Rs$6720$