The posters you see here (and in the da Vinci hallways) were created by my Geometry students as a way to learn, practice, and demonstrate their knowledge of constructing exact geometrical shapes, angles, and line segments using only a compass and unmarked straightedge.
Somewhere on one of the posters, each da Vinci Geometry student demonstrated how to do nine different constructions using a compass and an unmarked straightedge:
- Copy a line segment
- Construct a circle
- Construct a triangle that is congruent to another scalene triangle
- Construct an angle bisector (essentially, split an angle into two evenly)
- Construct a perpendicular bisector of a line segment
- Construct a regular hexagon, regular octagon, or 30°-60°-90° triangle
- Construct the perpendicular to a given line through an external point
- Construct a line parallel to a given line and through an external point
- Construct a non-equilateral isosceles triangle
If you look closely, you can see some pencil marks from their construction process!
I got the idea and some materials for this project from a teacher in San Francisco who goes by the name cheesemonkeysf online. At her blog, she wrote: “Einstein was right — imagination IS more important than knowledge. […]I created this Constructions Castle project to give students plenty of practice doing constructions while also giving them a chance to develop their understanding of how shapes and angles fit together.”
Thanks to cheesemonkeysf for the great idea and to the Geometry class for doing such a fabulous job on this project. Your posters are much more beautiful than a pile of test papers!