# Perpendicular and parallel straight lines 1 1/2

**Lesson Aims**During the folding processes the pupil will relate to perpendicular and parallel lines and segments.

**Name of Model**There is no model in this lesson.

**The Lesson Structure**According to planned curriculum.

**Lesson content**This is a prepatory lesson to the next lesson about parallel and perpendicular lines and segments with the model of a dress. In the lesson the pupils investigate the properties of parallel and perfpendicular lines using their measuring tool.

**Prior Knowledge**The concepts of angle,a right angle and a square.

**Materials**Origami sheets 15/15 cm and measuring tool.

**Additional knowledge****For the teacher.**If two straight segments are both perpendicular to a third straight line then the two segments are parallel.

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A transversal line that is perpendicular to one of two parallel lines will also be perpendicular to the other parallel line.