How To Find The Perimeter Of A Rectangle

We have the following rectangle. It's got a width of three centimeters and a length of five centimeters. If we want to calculate the perimeter of this rectangle, the first thing we've got to know is that the perimeter is the length around the outside of the shape.

To work this out, we need to realize that this length here is the same as this length here: three centimeters. So tally this up. And this length here is the same as this one here, so this is five centimeters.


The next and final step is to add these four lengths together. Three plus five plus three plus five gives us a perimeter of 16 and remember our unit is centimeters. We're still dealing with a single dimension.

We’re still dealing with just length. We have not found an area. So be very careful when using your units.

Just to recap. To find a

of a rectangle you need to know what the lengths of all the sides are. Once you know that, you just add them together.

And remember your units do not change from the original units used in the lengths. So, that was three plus five plus three plus five which comes to 16 and our units was centimeters.
And that's how to find the perimeter of a rectangle.