| A | B |
|---|
| polygon | A closed plane figure with line segments as sides. |
| regular polygon | A polygon with all sides congruent and all angles congruent. |
| triangle | A polygon with three sides. |
| quadrilateral | A polygon with four sides. |
| pentagon | A polygon with five sides. |
| hexagon | A polygon with six sides. |
| septagon OR heptagon | A polygon with seven sides. |
| octagon | A polygon with eight sides. |
| nonagon | A polygon with nine sides. |
| decagon | A polygon with ten sides. |
| acute triangle | A triangle with three acute angles. |
| obtuse triangle | A triangle with one obtuse angle. |
| right triangle | A triangle with one right angle. |
| equilateral triangle | A triangle with all sides and angles equal. |
| isosceles triangle | A triangle with TWO congruent sides. |
| scalene triangle | A triangle that has no congruent sides. |
| parallelogram | A quadrilateral with each pair of opposite sides parallel and congruent. |
| rectangle | A parallelogram with four right angles. |
| rhombus | A parallelogram with all sides congruent. |
| square | A rectangle with all sides congruent. |
| trapezoid | A quadrilateral with only one pair of opposite sides parallel. |
