| A | B |
|---|
| Ray | A line starting at one point and extending indefinitely in one direction |
| Angle | A figure formed by 2 rays with a common endpoint |
| Complementary angles | 2 angles whose sum is 90 degrees |
| Supplementary angles | 2 angles whose sum is 180 degrees |
| Vertical angles | Opposite angles formed when 2 lines intersect |
| Adjacent angles | Angles with a common vertex and a common side between them |
| Linear pair | 2 adjacent angles whose exterior sides form a straight line |
| Midpoint | A point which divides a line segment into 2 equal parts. |
| Median | A line segment from a vertex of a triangle to the midpoint of the opposite side |
| Altitude | A line segment from a vertex of a triangle, perpendicular to the opposite side |
| Perpendicular Bisector | A line that is perpendicular to a line segment and also bisects the segment. |
| Angle Bisector | A ray through the vertex of an angle, which cuts the angle into 2 equal angles. |
| Point of Concurrency in a triangle | A point where 3 special lines for a triangle intersect |
| Circumcenter | Point of Concurrency for the 3 perpendicular bisectors of a triangle |
| Incenter | Point of Concurrency for the 3 angle bisectors of a triangle |
| Orthocenter | Point of Concurrency for the 3 altitudes of a triangle |
| Centroid | Point of Concurrency for the 3 medians of a triangle |
| Concurrent Lines | Lines that go through a single point |
| Hypothesis and Conclusion | The 2 parts of a conditional statement |
| Converse of a conditional statement | Formed when the hypothesis and conclusion are interchanged |
| Perpendicular Lines | Lines that intersect to form 2 equal adjacent angles |
| Right Angles | The equal angles formed when 2 perpendicular lines intersect. 90 degrees |
| Parallel lines in a plane | Lines that do not intersect |
| Corresponding angles. eg. Angles 8 and 6 etc. | A pair of angles in corresponding positions when lines are cut by a transversal |
| Alternate interior angles | A pair of interior angles,diagonally across from each other,when lines are cut by a transversal "Z angles" |
| Alternate exterior angles | A pair of exterior angles diagonally across from each other when lines are cut by a transversal |
| Consecutive interior angles | A pair of interior angles,on the same side of the transversal, when lines are cut by a transversal |
| Slope | "rise" over "run" |
| Quadrilateral | A figure with 4 sides. |
| Parallelogram | A quadrilateral with opposite sides parallel |
| Trapezoid | A quadrilateral with one pair of opposite sides parallel. |
| Rectangle | A parallelogram with one right angle. |
| Rhombus | A parallelogram with all 4 sides equal. |
| Kite | A quadrilateral with 2 pairs of congruent adjacent sides. |
| Square | A parallelogram that is both a rectangle and a rhombus. |
| Pentagon | A polygon with five sides. |
| Hexagon | A polygon with six sides. |
| Heptagon | A polygon with seven sides. |
| Octagon | A polygon with eight sides. |
| Nonagon | A polygon with nine sides. |
| Decagon | A polygon with ten sides. |
| Dodecagon | A polygon with twelve sides. |
| n-gon | A polygon with n sides. |
| Diagonal | A line segment joining 2 nonadjacent vertices in a polygon. |
| Equilateral Polygon | A polygon with all sides equal |
| Equiangular Polygon | A polygon with all angles equal |
| Regular Polygon | A polygon which has all sides equal and all angles equal |
| Distance from a point to a line | The length of the perpendicular segment from the point to the line. |
| Isosceles Trapezoid | A trapezoid whose nonparallel sides are the same length. |
