Question

the length of a rectangle is twice its width if its perimeter is 54 find its length

Answer 1

Let the length of rectangle be L and breadth be B As per given condition L=2B Perimeter of rectangle is L+B Given L+B=54 Substituting L=2B 3B=54 B=18 As Length is asked which is 2B Length of rectangle is 2x18=36.

Answer 2

let the breadth of the rectangle be b
length= 2b
perimeter = 54 cm
perimeter of rectangle= 2(l+b)
                              = 2(2b+b)
2 × 3b = 54cm
6b = 54 cm
b = 54cm ÷ 6
   = 9 cm
length = 2b = 9 × 2 = 18cm