Measuring an Angle

Using a protractor

Angles are measured using a protractor. You can guess the rough size of an angle by looking to see if it's acute or obtuse, but you'll need a protractor for a precise measurement.

Here's how to use a protractor to measure an angle:

- Line up the protractor so the 'cross hair' is exactly on the angle.
- Line up one of the lines with the 0 line on the protractor.
- See which numbers the angle comes between. If it is between 30 and 40, the angle must be thirty something degrees.
- Count the small degrees up from 30. In this example, the angle is 35°.