| A | B |
|---|
| plane figure | flat shape, two dimensions |
| line | a straight path of points that goes on and on |
| point | an exact location in space |
| line segment | a part of a line that has two endpoints |
| ray | a part of a line that has one endpoint and continues endlessly in one direction |
| collinear points | three or more points that lie on the same straight line |
| coplanar | geometric objects that lie on the same plane |
| two dimensional | having two dimensions: length and width |
| endpoint | point marking the end of a line segment or ray |
| vertex | the point where two rays meet |
| angle | a figure formed by two rays that have the same endpoint |
| intersecting | crossing at one point |
| right angle | an angle of ninety degrees |
| acute angle | an angle less than 90 degrees |
| obtuse | an angle more than 90 degrees |
| protractor | a tool for measuring the size of angles |
