How to Read a Ruler in Centimeters
- 1). Notice the ruler's larger markings are labeled centimeters (cm) and the smaller markings are labeled millimeters (mm), and that the ruler measures a total of 12 inches on one side and 30 centimeters on the other.
- 2). Examine the millimeter lines more closely, observing that there are 10 mm for every centimeter, which corresponds with decimal readings when measuring fractions or portions of a centimeter.
- 3). Begin by drawing several lines on a piece of paper by using one of the edges of the ruler to keep the lines straight. Using the metric edge, line up the ruler so that the left end of the pencil mark lines up with the end of the ruler, then locate where the line ends on the ruler. Count the centimeters and write the number under the line. If the end of the line falls between centimeters, count how many millimeters past the last centimeter reading that the line goes. For example, If the line measures 3 cm plus 6 mm, then the line calculates out to 3.6 cm.
- 4). Since measuring lines can be boring, try measuring other items around the house or desks and books if you're in a classroom. Measure each other by marking height on the wall, then using the ruler to find height in centimeters.
