| A | B |
|---|
| arc | part of a circle |
| diameter | endpoints on the circle, passing through the middle |
| radius | half of a diameter |
| acute angle | less than 90 degrees |
| right angle | 90 degrees |
| obtuse angle | more than 90 degrees |
| complimentary | adds to 90 degrees |
| supplementary | adds to 180 degrees |
| polygon | closed object with at least three sides |
| quadrilateral | 4 sided closed object |
| triangle | 3 sided closed object |
| pentagon | 5 sided closed object |
| hexagon | 6 sided closed object |
| octagon | 8 sided closed object |
| decagon | 10 sided closed object |
| parallel lines | lines that never intersect |
| intersecting lines | lines that cross each other |
| perpendicular lines | intersect at a right angle |
| midpoint | divides a segment into two equal lengths |
| segment bisector | a line that goes through the midpoint of a segment |
| compass | tool used to draw circles and arcs |
| chord | segment with endpoints on the circle |
| rectangle | parallelogram with 4 right angles |
| square | paralellogram, 4 congruent sides, 4 right angles |
| vertical angles | opposite angles resulting from intersecting lines |
