Explain how angles are measured in degrees and that a perfectly straight line is 180 degrees.
Teach the three types of angles: acute, obtuse and right. Explain that they are classified based on their range of degrees. A right angle is exactly 90 degrees and forms a perpendicular line with the base line. An angle is acute if it is less than 90 degrees, and obtuse if it is greater than 90.
Give students a protractor and explain how it is used. Show them how to place the opening on the vertex where two line segments meet to calculate the degree of an angle.
Create some sample problems that students can complete for practice. Have them calculate the degree of the angle and the angle classification using a protractor. Explain any mistakes that are made and how they can be corrected.