The length of a rectangle is twice the width , if its perimeter is 80, what is the dimension of the rectangle?

Question

The length of a rectangle is twice the width , if its perimeter is 80, what is the dimension of the rectangle?

Answer 1

Hey Jhen:

 

This question wants you to find the dimensions of the rectangle--in short, the size of each side.  You probably know that the perimeter of a rectangle (or of any polygon / shape) is the sum of its sides.  For rectangles, we know there are four sides, with two long sides (length) and two short sides (width).  For this particular rectangle, we know that the length is twice the width, with the sum of all four sides = 80.  So it's an algebra problem:

 

Let w = width

So length: = 2w (because "twice the width")

There are two w sides, and two 2w sides, so the perimeter = w + w + 2w + 2w = 80

Simplified:  6w = 80

So: w = 13.33, or 13 and 1/3 (which is 80 divided by 6)

So length = 2w = 26.66, or 26 and 2/3 (which is 2 multiplied by 13.33)

Dimension:  13.33 by 26.66

 

You can check, if you have the time, by adding up:  13.33 + 13.33 + 26.66 + 26.66 = 79.98

The difference of .02 is the result of approximating 1/3 as .33 and 2/3 as .66

 

Hope this helps!

 

Evan Clary