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How to Read the Measurement on a Protractor

A protractor is a mathematical tool designed to measure or create exact angles. They are typically flat, made out of plastic and look like a semicircle. The inside of the protractor is usually hollow and the round edge of the protractor is marked with small lines indicating degrees. The straight edge of the protractor is generally marked with inches so it can be used as a ruler. Measuring angles with a protractor is fairly simple.

Instructions

- 1
  Find the center hole on the straight edge of the protractor and place it over the point of the angle that needs to be measured.
- 2
  Rotate the protractor so that its straight edge is parallel with one of the sides of the angle. Ensure the hole in the protractor stays on the point of the angle.
- 3
  Find the point on the protractor where the second side of the angle extends past the protractor's curved edge. Read the number written on the curved edge of the protractor at the point where the angle line intersects it. You may need to count up or down from a marked number in order to determine the measurement line's value. This is the measurement of the angle, given in degrees.

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