| A | B |
|---|
| polygon | a closed figure made of line segments that meet at their endpoints |
| regular polygon | a polygon with all congruent sides and angles |
| diagonal | a segment that joins any 2 non-consecutive veritices |
| perimeter | the sum of the lengths of the sides of a polygon |
| quadrilateral | a 4-sided polygon |
| pentagon | a 5-sided polygon |
| hexagon | a 6-sided polygon |
| octagon | a 8-sided polygon |
| decagon | a 10-sided polygon |
| parallelogram | a quadrilateral with 2 pair of parallel sides |
| trapezoid | a quadrilateral with one pair of parallel sides |
| rectangle | a parallelogram with 4 congruent angles |
| rhombus | a parallelogram with 4 congruent sides |
| square | a parallelogram with 4 congruent sides and 4 congruent angles |
| acute triangle | a triangle with 3 acute angles |
| obtuse triangle | a triangle with 1 obtuse angle |
| right triangle | a triangle with 1 right angle |
| scalene triangle | a triangle with no congruent sides |
| isosceles triangle | a triangle with 2 congruent sides |
| equilateral triangle | a triangle with 3 congruent sides |
| angles-sides property | the longest side is opposite the largest angle |
| angles property | the sum of the sides of a triangle is 180 degrees |
| sides property | the sum of 2 sides of a triangle must be more than the 3rd side |
| sum of angles of a polygon | 180 times the number of sides minus 2 |
| each angle of a regular polygon | the sum of the angles divided by the number of sides |
