| A | B |
|---|
| reflex angle | an angle greater than 180 degrees |
| acute angle | measures between 0 and 90 degrees |
| adjacent angles | angles with a common side |
| circle | measures 360 degrees |
| equilateral triangle | a triangle with all sides of equal length |
| triangle | measures 180 degrees |
| isosceles triangle | triangle with at least 2 sides of equal length |
| parallelogram | quadrilateral with 2 pairs of parallel sides |
| polygon | a closed 2-dimensional figure |
| quadrangle | polygon with 4 sides |
| quadrilateral | quadrangle |
| ray | a straight path that extends infinitely from a point |
| regular tessellation | made up of only 1 kind of regular polygon |
| right angle | measures 90 degrees |
| rhombus | quadrilateral whose sides are all the same length |
| scalene triangle | triangle with 3 sides of different lengths |
| tessellation | arrangement of shapes that covers a surface completely without overlaps or gaps |
| trapezoid | quadrilateral with 1 pair of parallel sides |
| vertical angle | opposite angles; do not share a common side |
| vertex | the point where the rays of an angle meet |
| straight angle | measures 180 degrees |
| obtuse angle | measures between 90 and 180 degrees |
| nonconvex (concave)polygon | polygon in which at least 2 sides are pushed in |
| regular polygon | polygons whose sides all have the same length and angles the same size |
| congruent | figures with the same shape and size |
