| Rectangle | | Same size, same shape. |
| Equiangular | | Lines that are not coplanar. |
| Supplementary | | A polygon with 5 sides. |
| Tangent | | The distance from the center of a regular polygon to a side. |
| Corresponding | | Points all in one line. |
| Hypotenuse | | Two angles whose measures have the sum of 180. |
| Pentagon | | A segment joining two non-consecutive vertices of a polygon. |
| Collinear | | The sum of the length of the sides of a polygon. |
| Triangle | | A segment whoes endpoints lie on a circle. |
| Chord | | A number that describes the steepness of a line. |
| Perimeter | | A chord that contains the center of a circle. |
| Isosceles | | Two angles in corresponding positions relative to two lines. |
| Height | | A segment from a vertex to the midpoint of the opposite side. |
| Angle | | A polygon with four sides. |
| Diameter | | A quadrilateral with four right angles. |
| Theorem | | A statement excepted as true without proof. |
| Similar | | A quadrilateral with four right angles and four congruent sides. |
| Apothem | | A line that intersects a circle in exactly one point. |
| Median | | A polygon with 8 sides. |
| Parallelogram | | A triangle with two congruent sides. |
| Straight | | An angle with a measure of 180. |
| Diagonal | | A polygon with three sides. |
| Decagon | | A line that contains a chord. |
| Slope | | The ray that divides the angle into 2 congruent angles. |
| Congruent | | The length of the altitude of a polygon. |
| Rhombus | | A polygon with 10 sides. |
| Octagon | | A quadrilateral with both pairs of opposite sides parallel. |
| Equilateral | | Coplanar lines that do not intersect. |
| Acute | | Two angles whose measures have the sum of 90. |
| Bisector | | A polygon that is equilateral and equiangular. |
| Obtuse | | An angle with a measure of 90. |
| Regular | | The side of a right triangle opposite the right angle. |
| Complementary | | A triangle with all sides equal. |
| Quadrilateral | | The point that divides a segment into two congruent segments. |
| Opposite | | An angle with measure between 0 and 90. |
| Segment | | A quadrilateral with four congruent sides.s |
| Parallel | | A triangle with all angles equal. |
| Square | | A figure formed by two rays with a common endpoint. |
| Right | | An angle with measure between 90 and 180. |
| Skew | | Points all in one plane. |
| Coplanar | | Two points on a line and all the points between them. |
| Midpoint | | Two rays with a common endpoint pointing in opposite directions. |
| Postulate | | Same shape, different size. |
| Secant | | A statement that can be proved. |
