| A | B |
|---|
| ray | has one endpoint and one end that continues on |
| line segment | part of a line; has two endpoints |
| line | goes on and on in both directions |
| plane | flat surface |
| point | names a specific location with a letter |
| acute angle | angle measuring less than 90 degrees |
| right angle | angle measuring exactly 90 degrees |
| obtuse angle | angle measuring more than 90 degrees but less than 180 degrees |
| straight angle | angle measuring exactly 180 degrees |
| parallel lines | lines that will never touch |
| perpendicular lines | lines that touch or cross at a 90 degree angle |
| intersecting lines | lines that touch or cross |
| polygon | a closed figure with straight sides |
| pentagon | a 5-sided polygon |
| hexagon | a 6-sided polygon |
| octagon | an 8-sided polygon |
| quadrilateral | a 4-sided figure |
| triangle | a 3-sided figure |
| trapezoid | a quadrilateral with only one set of parallel sides |
| rhombus | a "lazy" square |
| parallelogram | a "lazy" rectangle |
| square | a quadrilateral with congruent sides and right angles |
