How to use a centimeter ruler?

To use a centimeter ruler, place the edge of the ruler at one end of the object or distance you want to measure. Make sure the zero mark is aligned with the starting point. Then, read the measurement where the other end of the object aligns with the numbered markings on the ruler, counting the centimeters and any additional millimeters if needed. For accuracy, ensure the ruler is straight and parallel to the object being measured.