Step 1. Place the origin over the point,or the vertex, of the angle in which you are measuring.
Step 2. Align the bottom line on the protractor with the base line of the angle.
Step 3. Follow the top line of the angle up to the measurements on the protractor's arc.
Step4.If the lines of the angle measure are short like the picture below then to get an accurate measurement, extend the angle's line until it passes the protractor. I like to use a piece of paper.
Protractors are used to measure the measure of an angle. One area that people get confused about is the two sets of measurements most protractors have. A helpful hint that should help when deciding which set of numbers to use is " Does this angle look greater that 90 degrees?"