To read centimeters on a tape measure, align the object you are measuring with the zero centimeter mark and find the point where the object ends on the scale.
Understanding the metric side of a tape measure, which is typically marked in centimeters (cm) and millimeters (mm), is straightforward. The scale is based on units of 10, making calculations easy.
Locating the Centimeter Scale
Most tape measures have two scales: one in inches and feet, and the other in centimeters and meters. The centimeter scale usually features numbers that increase incrementally, indicating whole centimeters.
- Centimeter Marks: These are typically longer lines with numbers labeled (e.g., 1, 2, 3, ...). Each numbered mark represents a full centimeter.
- Millimeter Marks: The smaller lines between centimeter marks represent millimeters (mm). There are 10 millimeters in each centimeter (1 cm = 10 mm).
Steps for Reading Centimeters
Following the principle shown in the reference, reading a measurement involves starting at zero and noting the endpoint.
- Find the Zero Mark: Place the very beginning of the tape measure (often a metal hook or the marked '0') exactly at the start of the object you are measuring. According to the reference, you need to "place the end of our rectangle. Right at the zero centimeter mark".
- Extend the Tape: Unroll the tape measure along the object until you reach its end.
- Identify the Endpoint: Locate where the end of the object aligns with the markings on the tape measure. The reference mentions then to "find the end of the rectangle".
- Read the Whole Centimeters: Note the last numbered centimeter mark before the end of the object.
- Read the Millimeters: Count the smaller millimeter lines between the last whole centimeter mark and the object's endpoint. Each small line is 1 mm.
Examples
Here’s how to interpret common readings:
- If the object ends exactly on the '10' mark, the measurement is 10 cm.
- If the object ends on the 5th small line after the '10' mark, it's 10 centimeters and 5 millimeters. This is read as 10.5 cm.
- If the object ends on the 9th small line after the '25' mark, it's 25 centimeters and 9 millimeters. This is read as 25.9 cm.
Converting Millimeters to Centimeters
Since 10 mm equals 1 cm, you can easily convert millimeters to a decimal part of a centimeter by dividing the number of millimeters by 10.
| Measurement | Reading in cm | Explanation |
|---|---|---|
| 10 cm 0 mm | 10.0 cm | Exactly on the 10 cm line |
| 10 cm 5 mm | 10.5 cm | 5 mm = 0.5 cm |
| 10 cm 10 mm (= 1 cm) | 11.0 cm | Reaches the next whole centimeter mark (11 cm) |
By practicing these steps and understanding the relationship between centimeters and millimeters, you can accurately read measurements on the metric side of your tape measure.
