Vocabulary should be seen as an aid to communicating mathematical ideas. Examples of parallel lines in the environment include railway tracks or lines in a notebook.
Perpendicular lines are lines that intersect at right angles.
Examples include the intersection of a wall with the floor or ceiling, or the intersection of two streets in a town or city. Students have compared angles in previous grades using right angles or straight angles as benchmarks. At Grade 6, it is sufficient for students to recognize that a square corner is a right angle. A piece of paper folded twice produces a right angle. When beginning the study of geometry, it is helpful for students to keep track of the new terms and what they mean.