- Acute Triangle: a triangle with 3 acute sides
- Acute angle: an angle with a measure of less than 90°
- 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
- 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
- Point: a location is space that has no size
- Polygon: A closed figure with at least 3 sides
- 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
- Transversal: a line that intersects 2 other points
- Triangle: A polygon with 3 sides
- face: a surface of a figure
- trapezoid: A quadrilateral with exactly one pair of parallel sides