Question

The rectangular playground in a school is three times as long as it is wide. The area of the playground is 75 square meters. When is the perimeter of the playground?

Answer 1

as l=3b
area =lb=75
3b^2=75
b^2=25
b=5 m
perimeter=2(l+b)=2(5+15)=40 m

Answer 2

Let breadth be x, then length = 3x, then.
=>Area of rectangle = length * breadth
=> 75 = x*3x
=> $\frac{75}{3}$ = x²
=> 25 = x²
=> √25 = x
=> 5 = x
So, length = 3 * x=3*5 = 15
And, breadth = x = 5.
Then, perimeter = 2(length + breadth)
perimeter = 2(15+5)
perimeter = 2*20 = 40m