| A | B |
|---|
| Point | An exact location in space. |
| Line | A collection of points that go in two directions for infinity. |
| Line Segment | Part of a line having two endpoints. |
| Ray | A line that has one endpoint and goes on forever in the other direction. |
| Angle | Two rays having a common endpoint. |
| Vertex | The point at which two lines meet to form an angle. |
| Plane | An endless flat surface determined by three points. |
| Right angle | An angle that measures 90 degrees. |
| Obtuse angle | An angle that measures greater than 90 degrees and less than 180 degrees. |
| Acute angle | An angle that measures less than 90 degrees. |
| Reflex angle | An angle that measure more than 180 degrees, but less than 360 degrees. |
| Straight angle | An angle that measures 180 degrees and forms a line. |
| Congruent angles | Angles that have the same measure. |
| Complimentary angles | Two angles whose sum equals 90 degrees. |
| Supplementary angles | Angles whose sum equals 180 degrees or a straight angle. |
| Angle bisector | A ray that bisects an angle into two equal angles. |
| Transversal | A line that intersects two or more other lines |
| Vertical angles | Angles that are positioned across from each other when two lines intersect. These angles have the same measure. |
| Corresponding angles | Angles that are in the same position from one line to another. These angles have the same measure. |
| Intersecting Lines | These lines meet at a point |
| Parallel Lines | These lines are on the same plane, but never meet. |
| Perpendicular Lines | These lines intersect to form 90 degree angles. |
| Skew Lines | Lines that are neither parallel nor intersecting. |
| Polygons | Closed plane figures with sides that are line segments. |
| Regular Polygons | All sides of this polygon are equal. |
| Quadrilateral | A polygon with 4 sides. |
| Triangle | A polygon with 3 sides. |
| Pentagon | A polygon with 5 sides |
| Hexagon | A polygon with 6 sides. |
| Heptagon | A polygon with 7 sides. |
| Octagon | A polygon with 8 sides. |
| Nonagon | A polygon with 9 sides. |
| Decagon | A polygon with 10 sides. |
| Convex Polygon | All diagonals are withing the polygon. |
| Concave Polygon | Some diagonals are outside the area of the polygon. |
| Perimeter | Distance around a polygon |
| Area | Number of square units in a figure. |
| Congruent Figures | Figures that are the same size and shape |
