K-5 friendly lesson
Try one idea, then jump into the activity.These lessons are designed to feel short, friendly, and easy to follow.

Measure angles with a protractor

A protractor is a precision tool for measuring turns. You can read angle size in degrees (°).

Lesson 6

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°.