The Circle Protractor is a full 360-degree protractor that helps students measure and understand angles all around a circle. On the interactive whiteboard, you can enlarge, rotate, and move the tool to demonstrate angle measurements. It’s especially useful for measuring reflex angles (greater than 180°) that a half protractor cannot show.
How it works:
Place the circle protractor on the board by clicking and dragging.
Rotate it to align the baseline with one side of the angle.
Use the center mark to line up the vertex of the angle.
Read the measurement where the other side of the angle meets the scale.
You can also draw against the protractor to create accurate angles.
Classroom uses:
Demonstrate reflex angles: Show students how to measure angles larger than 180°.
Practice together: Have students measure and compare different angles in shapes.
Explore full rotations: Use the 360° scale to explain how angles add up to a full circle.
💡Tip: Draw a circle on the board and use the protractor to measure central and reflex angles. This makes it easy for students to see how fractions of a circle connect to degrees, helping them understand both geometry and fractions at the same time.