#### If you had a rectangle with a perimeter of 10, you could use a geoboard to figure out how long the sides of your rectangle might be.

#### Click here for the virtual geoboard or use one from your school.

If you are using the virtual geoboard, select any colour of elastic and drag it up onto the board by holding down the left mouse key. When you are where you want to place the elastic, release your left mouse key. Move your mouse around and notice the elastic stretches as your mouse moves.

**Start out** by stretching an elastic band over four pegs. When you are over four pegs, click your mouse to set the elastic in place. (You can follow this same procedure if you are using a geoboard from your classroom.)

#### Place your mouse in the middle of the elastic. Hold down your mouse button to move it. Pull it down so that it is one peg below where you started at each end, so you have a rectangle shape. You will have to grab the elastic in the middle twice to do this.

#### Count the lengths of all the sides and add them up.

#### 4 + 4 + 1 + 1 = 10

#### You have created a rectangle with a perimeter of 10. But is this the only shape of rectangle that has a perimeter of 10?

#### Try creating a rectangle that is 3 long by 2 wide on your geoboard, and then calculate the perimeter.