Question

The perimeter of a rectangle is 20 cm. The length is 7 cm. What is the area?

Answer 1

Hey there!

So we know the perimeter is 20 cm. Let's make our formula for this.

2L + 2W = 20

The formula for the area of a rectangle is L x W. Let's make this into our formula and fill it in as time goes.

L x W

Our Length is measured at 7 cm, so let's fill that into our formulas.

2(7) + 2W = 20
7 * W = x

Let's use some basic algebra to solve for our perimeter.
2(7) + 2W = 20
14 + 2W = 20
2W = 6
W = 3

This means our Width is 3. Now all we have to do is solve for our area since we have our dimensions.

7 x 3 = 21

The area of the rectangle is 21 cm^2.

I  hope this helps!