| __ | 1. | acute angle | | A. | any angle less than 90 degrees |
| __ | 2. | adjacent angles | | B. | two angles that together have a sum of 180 degrees |
| __ | 3. | complementary angles | | C. | two angles opposite from each other & are always congruent |
| __ | 4. | linear pair | | D. | two angles that together have a sum of 90 degrees |
| __ | 5. | obtuse angle | | E. | any angle more than 90 degrees |
| __ | 6. | right angle | | F. | one angle that has a measure of exactly 180 degrees |
| __ | 7. | straight angle | | G. | an angle that has a measure of exactly 90 degrees |
| __ | 8. | supplementary angles | | H. | two angles that are side by side, sharing a common side |
| __ | 9. | vertex | | I. | two adjacent & supplementary angles forming a straight line |
| __ | 10. | vertical angles | | J. | the common endpoint of two rays in an angle |