Question

the length of the rectangle is 7 by 5 of its breadth. if its perimeter is 144 m, what is its area?

Answer 1

p= 2(l+b)
144=2(7/5+x)
144=2×12/5x
144=24/5x
x=144×5/24
x=30
area=l×b
=7/5×30
=43 cm² ans

Answer 2

Answer:$1260\ m^2$

Step-by-step explanation:

Let x be the breadth of the rectangle.

Then the length of the rectangle=$\frac{7}{5}\times x=\frac{7x}{5}$

The perimeter of rectangle is given by:-

$Perimeter=2(l+b)\\\Rightarrow\ 144=2(\frac{7x}{5}+x)\\\Rightarrow144=2(\frac{12x}{5})\\\Rightarrow\ 24x=144\times5\\\Rightarrow\ x=\frac{720}{24}\\\Rightarrow\ x=30$

∴Breadth= 30 m

and length=$\frac{7\times30}{5}=42\ m$

The area of rectangle=$l\times b=42\times30=1260\ m^2$