1. Chapter 2 : Angles
Vocabulary Terms

2. 1. angle
A geometric figure formed by two rays with a common end point

3. 2. protractor
A tool used to measure angles

4. 3. Acute angle
An angle that is greater than 0 degrees and less than 90 degrees

5. 4. Right angle
An angle that is equal to 90 degrees

6. 5. Obtuse angle
An angle that is greater than 90 degrees and less than 180 degrees

7. 6. Straight angle
An angle that is equal to 180 degrees

8. 7. Adjacent angles
Two angles that have a common vertex and a common ray

9. 8. Complementary angles
A pair of angles whose measures have a sum 90 degrees

10. 9. Supplementary angles
A pair of angles whose measures have a sum of 180 degrees

11. 10. Congruent angles
Angles that have the same measure

12. 11. Vertical angles
Angles formed by intersecting lines

13. 12. Angle bisector
A ray that divides an angle into two congruent angles