How Do You Measure Angles?

Use a protractor to measure the number of degrees in an angle. Place the protractor over the angle so that one line goes along the protractor's zero degrees line, the vertex is at the center of the zero degrees line, and the second line passes through another number on the protractor.

  1. Align the protractor with the angle

    Place the zero-degree line of the protractor over one of the lines in the angle, and line it up so that the point of the vertex is at the center of the zero-degree line on the protractor.

  2. Make the second line of the angle pass through one of the degree measurements on the protractor

    The other line of the angle should pass through the curved edge of the protractor, intersecting one of the degree measurement markers. If the other line segment points away from the protractor's curved edge, turn the protractor, and align the first line of the angle with the other side of the protractor's zero line to make the second line pass through the curved edge.

  3. Read the measurement on the protractor

    Count the degree numbers on the protractor until you get to the point where the second line segment of the angle intersects the protractor's curved edge. The number at this intersection is the measurement of the angle in degrees.