The width of the rectangle is x cm. If the perimeter of the rectangle is 24 cm, find an expression in terms of x, for the length of the rectangle.

Answer 1

The formula of Perimeter of Rectangle = 2( L + X )

where suppose L is the length and X is the width of the rectangle given in the problem,

so we can write the equation , 2( L + X ) = 24

eliminating bracket we get, 2L + 2X = 24

dividing both sides by 2 , 2L/2 + 2X/2 = 24/2

L + X = 12

L = 12- X

so expression for Length L, L = 12 - X

Answer 2

Hi, Marianne,

The width is X. Let's say the length is L. The perimeter is the sum of all sides, so:

Perimeter = 2X + 2L

24cm = 2X + 2L

rearranging,

2L = 24cm - 2X

or, L = 12cm - X

To check, assume X is 4cm. The equation tells us L should be 8cm (12 - 4).

Perimeter = 4+ 4+ 8+ 8 = 24cm.

Bob