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Perpendicular and Parallel Lines 
Materials

IntroductionThis 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 sidebyside 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 sidebyside; 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 counterexamples to help students understand both terms. The ProjectThe teacher should start by taping a starter sheet (page 118) at the front of the room. Use it to model each step. 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. 