Using Tools to Make Perpendicular Lines

Yesterday students learned about parallel and perpendicular lines, and how to draw them.  The tool we chose to start with was a triangular ruler, that has a 90° angle incorporated in its structure.  This led us to today's goal:

With a bag of different measuring tools in front of them, students first choose the one we know and demonstrated how to use it to create perpendicular lines.  Then, from the remaining tools left on their desks they needed to choose on that they thought they could use to create perpendicular lines.

After some discussion, and trying out one tool which we deemed would not work to accurately create a perpendicular line, they decided that we could use a protractor to help us in this endeavour.  Through a class demonstration, the students agreed that indeed this would work.  So then we set out to practice creating perpendicular lines alternating between the two measuring tools.