1. Approximate the measure of your angle. Angles can be categorized in three ways: acute, obtuse, and right. Acute angles are less than 90 degrees, obtuse angles are greater than 90 degrees, and right angles are exactly 90 degrees.
2. Place the origin over the center point, or vertex, of the angle you want to measure. The small hole in the middle of the protractor is the origin. Put the vertex of the angle with the center of the cross in the origin.
3. Rotate the protractor to line up one leg of the angle with the baseline. Maintain the vertex of the angle in the origin and rotate the protractor so that one of the legs of the angle falls on the baseline of the protractor.<span>The baseline is even to the edge, but is not the flat edge of the protractor. It is lined up with the center of the origin and the line projects to the start of the scale on either side.
</span>4. Follow the opposite leg of the angle up to the measurements on the protractor's arc. If the line does not pass through the protractor’s arc, make the angle's line longer until it does. You can align the edge of a piece of paper with the angle’s leg to pass beyond the edge of the protractor, continuing the line of the angle. The number the line passes through is the angle's measurement in degrees. <span><span> </span></span>
