What is the first step in measuring an angle with a protractor?

Place the center of the protractor on the vertex of the angle.

After placing the protractor's center on the vertex, what should you do next?

Rotate the protractor so that the 0-degree mark aligns with one side of the angle.

It provides a starting point for accurate measurement, ensuring the angle is measured from 0 degrees.

Rotate the protractor so the 0-degree mark is on the other side of the angle, ensuring the angle falls within the protractor's range.

Grade 9th Grade · Math · 45 min

I can accurately measure angles using a protractor.

Khan Academy · 3:26

Measuring angles using a protractor | Angles and intersecting lines | Geometry | Khan Academy

3 key concepts

1
To measure an angle using a protractor, place the center of the protractor on the vertex of the angle.
2
Rotate the protractor so that the 0 degree mark lines up with one side of the angle, and then read the measurement where the other side intersects the protractor.
3
Angles that measure less than 90 degrees are called acute angles, while angles that measure more than 90 degrees are called obtuse angles.

11 questions · Multiple choice & Short answer

Quick comprehension check

“Draw an angle. Use a protractor to measure the angle you drew, and write down the measurement in degrees.”

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Teacher GuideComplete lesson plan

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