| __ | 1. | acute triangle | | A. | A triangle with one angle whose measure is greater than 90˚. |
| __ | 2. | equilateral triangle | | B. | The shortest distance between any two points on a plane |
| __ | 3. | irregular polygon | | C. | A polygon in which all sides and angles are congruent. |
| __ | 4. | isosceles triangle | | D. | A polygon in which all sides and angles are not congruent. |
| __ | 5. | line | | E. | The part of a line having two end points. |
| __ | 6. | line segment | | F. | A triangle that has three congruent sides and angles. |
| __ | 7. | obtuse triangle | | G. | A triangle having two sides and two angles congruent. |
| __ | 8. | regular polygon | | H. | A triangle with no sides the same length. |
| __ | 9. | right triangle | | I. | A triangle with one right angle. |
| __ | 10. | scalene triangle | | J. | A triangle where all three angles are less than 90 degree |
| __ | 11. | acute angle | | A. | A quadrilateral with opposite sides parallell |
| __ | 12. | angle | | B. | An image or shape as it would be seen in a mirror. |
| __ | 13. | congruent angles | | C. | A shape that has two halves that are mirror images. |
| __ | 14. | line of symmetry | | D. | An angle whose measure is less than 90 degrees. |
| __ | 15. | obtuse angle | | E. | A shape rotated less than a full turn to look the same. |
| __ | 16. | parallelogram | | F. | An imaginary line folds an image and both look the same. |
| __ | 17. | reflection | | G. | Two rays meet at a vertex and measure the amount of a turn. |
| __ | 18. | reflection symmetry | | H. | Two angles whose measures are exactly the same. |
| __ | 19. | right angle | | I. | An angle whose measure is 90 degrees. |
| __ | 20. | rotation symmetry | | J. | An angle who greater than 90 degrees but less than 180˚. |