Question

length of a rectangle is thrice it's width . if perimeter is 84m ,find its length

Answer 1

(x+3x)2=84
8x=84
x=84/8=10.5
so length is 31.5

Answer 2

Width = x
Length = 3x
Perimeter = 84m = 2(l + b) = 2(3x + x)
> 84 = 2*4x
> 84 = 8x
> X = 84/8 = 10.5 m
Therefore
Length = 3x = 31.5 m