| A | B |
|---|
| triangle | a figure formed by 3 segments that meet at their endpoints |
| 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 tirangle with 2 congruent sides |
| equilateral triangle | a triangle with 3 congruent sides |
| 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 vertices |
| perimeter | the sume 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 | an 8 sided polygon |
| decagon | a 10 sided polygon |
