| A | B |
|---|
| acute angle | an angle which is less than a right angle |
| line segment | the part of a line between two endpoints |
| line | is straight and has a set of points that extend on forever in opposite directions |
| ray | the part of the line that starts at an endpoint and goes on forever in one direction |
| intersecting lines | lines that meet at a common point |
| parallel lines | lines on a flat surface that never intersect |
| perpendicular lines | lines that intersect at square corners |
| angles | formed by two rays that start out from the same point |
| right angle | an angle which forms a square corner |
| obtuse angle | an angle which is greater than a right angle |
| triangle | a shape with 3 sides and 3 angles |
| isoceles triangle | a triangle that has two sides of equal length |
| equilateral triangle | a triangle in which all sides are equal in length |
| scalene triangle | a triangle which has no sides of equal length |
