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Perpendicular and Parallel Lines

parallel and perpendicular lines


  • Pencils (1 per student)

  • Starter sheets, page 118 (1 per student)

  • Rulers (1 per student)

  • Crayons or colored pencils (2 colors per student)

  • The completed project prepared by the teacher before the lesson


This lesson teaches students to identify perpendicular and parallel lines. Perpendicular and parallel lines are recurrent topics. They continuously appear, in one form or another, at all levels of mathematics. However, at the elementary school level, a basic understanding and familiarity of both terms is usually all that is required.

Parallel lines can most simply be defined as “lines that are side-by-side and never touch, no matter how long we draw them.” Perpendicular lines can be defined as “lines that make a ‘T.’” Both of these definitions are somewhat incomplete—lines can be parallel and still not be side-by-side; and perpendicular lines can make an ‘L’-shape as a ‘T’-shape. Still, introducing such complications is best left for later lessons.

The teacher should draw examples and counter-examples to help students understand both terms.

parallel and perpendicular lines 2

The Project

The teacher should start by taping a starter sheet (page 118) at the front of the room. Use it to model each step.

parallel and perpendicular lines 3

The size of the sheet will make it slightly difficult for children in the back of the room to see, but this should not be a problem if the teacher is careful to explain each of the following steps.


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