2-D Icosahedron Construction

By: Tiffany Barney



Lovely Ladies and Gentlemen!

Can you create this figure below? What is it? Any ideas?


My lovely students, I'm sure you have realized by now this is the icosahedron. Today we will walk through how to create this figure above. For homework, you will construct this with ruler and compass.

Ms. Tiffany


1. Use the Calculator function to insert whatever length your sides will be. In this case we will use 6.00cm and 6.00 (inverse of the golden ratio)=3.71cm.

2. Construct a large segmetn across the screen.

3. Insert a perpendicular bisector to this segement. Make a circle centered on this intersection with radius of 6.00 cm.

4. Insert another circle with radius equal to 3.71cm, centered at the same point.

5. Use your prior knowledge to construct a hexagon. (The figure above gives great hints.)

6. Find the intersection point of the small circle and perpendicular bisector.

7. Construct arcs with length equal to the small radius in order to create equilateral triangles going in different directions.

8. Now that you've done the hard part, all you have to do is connect the vertices.


Do you think you can construst 2-D representatiosn of the other solids?