Measure angles with a protractor
A protractor is a precision tool for measuring turns. You can read angle size in degrees (°).
Do this: Read the concept below, then try the quiz or activity.
Concept
How to measure an angle:
1. Place the center hole on the angle vertex. 2. Line up one ray with the 0° baseline. 3. Read where the second ray crosses the scale. 4. Choose the correct scale (inner or outer) based on where 0 starts.
Angle types: - acute: less than 90° - right: exactly 90° - obtuse: between 90° and 180°
🎯 Example: If the ray crosses at 65°, the angle is 65° (acute).
Try it
Measure and classify.
1. Draw and measure an angle close to 35°. 2. Draw and measure an angle close to 90°. 3. Draw and measure an angle close to 125°. 4. Which is larger: 48° or 104°? 5. If one angle is 70° and another is 20°, what is their total?
Challenge: 6. Draw two adjacent angles that add to 180°.