There are two types of rulers you can use: the inch, or imperial, ruler and the centimeter, or metric, ruler.
Inches correspond to the imperial system, which is the main measuring system used in the US and a smattering of other countries.
Meanwhile, centimeters are part of the metric system, which is used around the world in both everyday life and science.
While we will be providing pictures you can use to follow our instructions, we recommend getting out your own ruler or measuring tape so you can follow along in real time.
