| A | B |
|---|
| complementary angles | Two angles whose measures have a sum of 90 degrees. |
| supplementary angles | Two angles whose measures have a sume of 180 degrees. |
| congruent angles | Angles that have the same measures. |
| vertical angles | The angles opposite each other when two lines intersect. They are congruent. |
| isosceles triangle | A triangle that has at least two congruent sides. |
| equilangular triangle | A triangle that has three conguent angles. Is also an equilateral triangle. |
| congruent sides | Sides that have the same lengths. |
| polygon | A closed plane figure made up of three or more line segments that intersects only at their endpoints. |
| regular polygon | A polygon with congruent sides and congruent angles. |
| convex polygon | A polygon in which every line segment connecting any two vertices lies entirely inside the polygon. |
| concave polygon | A polygon in which at least one line segment connecting any two vertices lies outside the polygon. |
| equilateral triangle | A triangle that has three congruent sides. Is also an equilangular triangle. |
| similar triangle | Triangles that have the same shape but not necessarily the same size. |
| transversal | A line that intersects two or more lines. |
| indirect measurement | Using similar figures to find a missing measurement that is difficult to find directly. |
| interior angles | When two parallel lines are cut by a transversal, four angles are formed on the inside of the parallel lines. |
| perpendicular lines | Lines that intersect at right angles. |
| exterior angles | When two parallel lines are cut by a transversal, four angles are formed on the outside of the parallel lines. |
| parallel | Two lines in the same plane that do not intersect. The also have the same slope. |
