Question

the ratio between the length and breadth of a rectangular field is 1:3 .its area is 3/4 hectares.what is rhe perimeter

Answer 1

Let the ratios be x and 3x. 
3/4 hectare= 7500 sq.m 
l ×b= area 
x × 3x= 7500 
3x²=7500 
x²=7500/3 
x=√2500 
=50 
breadth =x=50m. 
length= 3x = 3×50=150 m. 
perimeter=2(l + b),unit 
=2(50+150),m 
=2×200,m 
=400,m

Answer 2

Let the ratio be x

1 hectares = 10000 m^2

3/4 hectares=3/4*10000

7500 m^2

Area of rectangle=length *breadth

7500=x*3x

3x^2=7500 m^2

x^2=2500 sq. m

x=50 m

Length=50 m

Breadth=150