| A | B |
|---|
| Acute Angle | An Angle less than 90 degrees |
| Obtuse Angle | An angle more than 90 degrees and less than 190 degrees |
| Right Angle | An angle that is 90 degrees |
| Straight Angle | An angle that is 180 degrees |
| Reflex Angle | An angle that is more than 180 degrees. |
| Radius | A line drawn from the center of a circle to the outer edge. |
| Diameter | A line drawn through the center of a circle from one side of to the other side. |
| Adjacent Angles | Angles that are right next to each other. |
| Equilateral Triangle | A triangle where all 3 sides are congruent |
| Isosceles Triangle | A triangle in which 2 sides are congruent |
| Scalene Triangle | A triangle in which no sides are congruent |
| Congruent | Exactly the same shape and size |
| Regular Polygon | Polygon in which all the sides and angles are congruent |
| Parallel | Never meeting and always the same distance apart |
| Right Angle | A 90 degree angle |
| Perimeter | The distance around a closed 2-dimensional shape |
| Parallelogram | A quadrilateral with 2 pairs of parallel sides with opposite sides and opposite angles congruent |
| Polygon | A closed 2-dimensional figure that is made ip of line segments joined end to end |
| triangle | Three sided polygon |
| pentagon | Five sided polygon |
| heptagon | Seven sided polygon |
| nonagon | Nine sided polygon |
| dodecagon | Twelve sided polygon |
| quadrilateral | general term for a Four sided polygon |
| hexagon | Six sided polygon |
| octagon | Eight sided polygon |
| hexagon | Six sided polygon |
| regular polygon | All congruent sides and congruent angles |
| decagon | ten sided polygon |
| right triangle | a triangle with one 90 degree angle |
| acute triangle | a triangle with three acute angles |
| obtuse triangle | triangle with one obtuse angle |
| similar polygons | corresponding angles are congruent and corresponding sides are proportional |
| scale factor (ratio of similitude) | ratio of enlargement or reduction for similar polygons |
| rhombus | quadrilateral with all sides congruent, opposite angles congruent, and opposite sides parallel |
| square | quadrilateral with all sides congruent and all angles 90 degrees |
| rectangle | quadrilateral with opposite sides congruent and all angles 90 degrees |
| parallelogram | quadrilateral with opposite sides and opposite angles congruent |
| trapezoid | quadrilateral with one and only one pair of parallel sides |
