Question

the length of a rectangle is three times it's width. if the perimeter is 84 m, find the length of the rectangle​

Answer 1

Answer:

length of the rectangle is 31.5 m

Step-by-step explanation:

width = x

lenght = 3x

perimeter = 84 m

perimeter = 2 * ( l + b )

84 = 2 * ( 3x + x )

84/2 = 4x

42 = 4x

x = 42/4

x = 10.5

width = 10.5 m

length = 10.5 * 3

= 31.5 m

Answer 2

Answer:

31.5 m

Step-by-step explanation:

Algebra method-

Let width of a rectangle=x

Length of the rectangle=3x

Perimeter = 2(l+b)

                = 2(3x+x)

                = 2(4x)

84m          = 8x

84/8         = x

10.5          = x

Length = 3x

            = 3(10.5)

            = 31.5 m

Ratio method-

Perimeter=2(l+b)

1/2 Perimeter=l+b

Ratio of length to breadth=3:1

3+1= Total 4 parts

42  X 3 = 31.5m length

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