| Acute angle | an angle with a measure of less than 90° |
| Acute Triangle | a triangle with 3 acute sides |
| Adjacent angles | 2 angles that share a vertex and a side but no points in their interiors |
| Alternate Interior Angles | angles between 2 lines and on opposite sides of a transversal |
| Angle | a figure formed by 2 different rays that have the same endpoint |
| Angle Bisector | a ray dividing a given angle into two congruent angles each half the size of the given angle. |
| Angle of Depression | an ang;e formed by a horizontal line and a line of sight below it |
| Angle of Elevation | An angle formed by a horizontal line and a line of sight above it. |
| Area | The number of square units a figure encloses |
| Central Angle | an angle whose vertex is in the center of a circle. |
| Chord | a chord of a circle is a line segment whose endpoints are on the circle. |
| Circle | a circle is the set of all points that are equidistant from a given point, called the center. |
| Circumference | The distance around a circle |
| Complementary Angles | 2 angles whose sum adds to 90° |
| Cone | a figure with one circular base and one vertex |
| Congruent Angles | Angles that have the same measure |
| Congruent Figures | Congruent Figures are figures that have the same size and shape |
| Congruent Segments | Segments that have the same length |
| Coordinate Plane | The plane formed by 2 number liines that intersect at their zero points dividing the plane into 4 quadrants |
| Coordinates | Ordered pairs that identify points on a coordinate plane. |
| Corresponding angles | Pairs of nonadjacent angles that lie on the same side of a transversal of 2 lines and in correspondiing positions. |
| Corresponding angles of polygons | Matching sides of similiar or congruent figures |
| Cube | a rectangular prism with 6 congruent faces |
| Cylinder | a figure whose bases are circular , congruent and parallel to each other. |
| Decagon | a polygon with 10 sides |
| Diagonal of a polygon | a segment (line) that connects 2 non consecutive vertices. |
| Diameter of a circle | A chord passing through the center of a circle |
| Edge | The intersection of 2 faces of a figure. |
| Equilateral Triangle | A triangle with 3 congruelnt sides |
| face | a surface of a figure |
| Hypotenuse | In a right triangle, the hypotenuse is the longest side, which is opposite the right angle. |
| Isosceles triangle | A triangle with at least 2 congruent sides |
| Legs of a right triangle | the 2 shorter sides of the triangle |
| Line | a series of points that extend in 2 directions without end. |
| Obtuse Angle | An angle with a measure greater than 90° and less than 180° |
| Obtuse Triangle | a triangle with one obtuse angle |
| Octogon | a polygon with 8 sides |
| Parallel Lines | lines that lie in the same plane and do not intersect.. |
| Pentagon | a polygon with 5 sides |
| Perimeter | The distance around a figure |
| Perpendicular Lines | Lines that intersect ot form right angles |
| Plane | a flat surface that has no thickness and continues without end in all directions |
| Polygon | A closed figure with at least 3 sides |
| Point | a location is space that has no size |
| Pyramid | a figure with triangular fice that meet in a vertex and a base that is a polygon |
| Radius of a Circle | a segment that has one endpoint at the center of the circle and the other endpoint on the circle. |
| Rectangle | A parallelogram with 4 right angles |
| Right Angle | An angle whosse measure is 90° |
| Segment | A segemt is a part of a line with 2 endpoints |
| trapezoid | A quadrilateral with exactly one pair of parallel sides |
| Triangle | A polygon with 3 sides |
| Transversal | a line that intersects 2 other points |