Find the dimensions of a rectangle with a perimeter of 126 in. if the length is double that of the width.
A) The length is 42 in. and the width is 84 in.
B) The length is 21 in. and the width is 42 in.
C) The length is 42 in. and the width is 21 in.
D) The length is 24 in. and the width is 48 in.
E) The length is 48 in. and the width is 24 in.

Question

Quizplus · Accepted Answer

Let's call the width x. According to the problem, the length is double the width, so the length is 2x. The perimeter is the sum of all the sides, so:
perimeter = 2(length) + 2(width)
126 = 2(2x) + 2(x)
126 = 4x + 2x
126 = 6x
x = 21
So the width is 21 in. and the length is 2x or 42 in. The dimensions are 21 in. by 42 in. which matches option C.

Find the Dimensions of a Rectangle with a Perimeter of 126