The length of a rectangle is five times its width. If the perimeter of the rectangle is 84cm, find its area

Question

The length of a rectangle is five times its width. If the perimeter of the rectangle is 84cm, find its area

Answer 1

We know that the length of the rectangle is five times the width, so:

 

l = 5w

 

Where l is length and w is width. We also know that the perimeter is 84 cm, so:

 

2l + 2w = 84

 

Now we can plug in 5w for l since we found the equality earlier:

 

2(5w) + 2w = 84

 

and then solve for w:

 

10w + 2w = 84

12w = 84

w = 7

 

Now we know the width is 7 cm. Since the length is 5 times the width, the length is 35, and the area of the rectangle is 7 x 35 = 245 cm².