Math Misconceptions and Considerations HSG-CO.D.12 & 13
Look closely at errors in students’ work (formative assessment) to help you reflect and make instructional decisions to suit all students’ needs.
Why construct it when I can just draw it? It is very important that students understand the difference between a geometric construction and a sketch. Misconception: Students rely on their ability to measure using a ruler or a protractor since that is how they were taught to measure angles and segment.
What to do: To deter the use of measurement tools, don’t even have them available for students to use. Instead of rulers, use popsicle sticks. Instead of protractors, have compasses or patty paper for students. The only use of measurement that is used in constructions is a compass. Explain that when a student does a geometric construction there will be visible signs that it was done correctly such as arcs.