| A | B |
|---|
| polygon | a plane, closed figure formed by line segments |
| line segment | a part of a line that has two end points |
| equilateral triangle | all sides are the same length |
| isosceles triangle | at least two sides are the same length |
| scalene triangle | no sides are the same length |
| right triangle | a triangle with one right angle |
| acute triangle | all angles are less than 90 degrees |
| obtuse triangle | one angle is greater than 90 degrees |
| congruent polygons | polygons that have the same size and shape |
| line of symmetry | a line on which a figure can be folded so that the two parts fit exactly |
