| A | B |
|---|
| degree | a unit of measure used to describe the size of an angle |
| congruent | the same or equal |
| right angle | an angle that measures 90 degrees |
| obtuse angle | an angle that measures between 90 degrees and 180 degrees |
| angle | opening between two straight lines that meet as a vertex, measured by degrees |
| straight angle | an angle that measures 180 degrees |
| interior angle | an angle in the insides of a polygon |
| exterior angle | an angle on the outside of a polygon |
| acute angle | an angle that measures between 0 degrees and 90 degrees |
| polygon | a closed, flat shape whose sides are formed by line segments |
| regular polygon | a polygon that has all of its sides equal and all of its angles equal |
| triangle | polygon with 3 sides and angles |
| quadrilateral | polygon with 4 sides and angles |
| pentagon | polygon with 5 sides and angles |
| hexagon | polygon with 6 sides and angles |
| heptagon | polygon with 7 sides and angles |
| octagon | polygon with 8 sides and angles |
| nonagon | polygon with 9 sides and angles |
| decagon | polygon with 10 sides and angles |
| equilateral triangle | a triangle with all three sides the same length |
| isosceles triangle | a triangle with two sides the same length |
| scalene triangle | a triangle with no sides the same length |
| parallelogram | a quadrilateral in which both pairs of opposite sides are equal and parallel |
| rectangle | parallelogram with all right angles |
| rhombus | a quadrilateral that has all sides the same length |
| square | a rectangle with all four sides equal |
| trapezoid | a quadrilateral with one pair of adjacent and congruent lines |
| kite | a quadrilateral with two pairs of adjacent and congruent sides |
| parallel lines | lines that never meet no matter how long they are extended |
| diagonal | a line segment connecting two non-adjacent vertices of a polygon |
| symmetry | a mirror image |
| line symmetry | when a figure can be folded along a line so that the two halves match exactly |
| rotational symmetry | when an object looks the same after it has been turned or rotated |
| vertex | the corners of a polygon or angle |
