Question

The length of a rectangle is 5 centimeters less than twice it’s width. The perimeter of the rectangle is 80 cm. What are the dimensions of the rectangle?

Answer 1

The length is equal to 25.

The width is equal to 15.

l = 2w - 5

2l + 2w = 80

We have a value for l, so we can plug it into the second equation to solve for w.

2(2w - 5) + 2w = 80

Distributive property.

4w - 10 + 2w = 80

Combine like terms.

6w - 10 = 80

Add 10 to both sides.

6w = 90

Divide both sides by 6.

w = 15

Now that we have a value for w, we can plug it into the original equation to solve for l.

l = 2(15) - 5

l = 30 - 5

l = 25