| __ | 11. | Acute angle | | A. | Unit of measure used for angles |
| __ | 12. | Adjacent angles | | B. | Angle whose measure is 180 degrees |
| __ | 13. | Complementary angles | | C. | Angle whose measure is less than 90 degrees |
| __ | 14. | Degree | | D. | Angle whose measure is greater than 90, less than 180 |
| __ | 15. | Obtuse angle | | E. | Angle whose measure if 90 degrees |
| __ | 16. | Perpendicular lines | | F. | Lines that form a right angle |
| __ | 17. | Right angle | | G. | Angles with same vertex and one common side |
| __ | 18. | Straight angle | | H. | Two angles whose measure adds to be 90 degrees |
| __ | 19. | Supplementary angles | | I. | Angles with same vertex and sides formed by the same lines |
| __ | 20. | Vertical angles | | J. | Two angles whose measure adds to be 180 degrees |