contents make an icosahedron!explore
Icosa- means twenty; -hedron means base. Icosahedrons have twenty bases (or faces).

Before you start, make sure that your compass is set to a radius no larger than two inches (and smaller is safer), if you are using 11" or 12" paper. You have lots of circles to draw!

1. Draw two circles. Turn your paper horizontally, and make sure the first circle is complete.
  2. Draw two more circles as shown.
3. Draw two more circles to the right of the first four, to make six.  
  4. Draw two more circles as shown. You will need eight complete circles.
5. Draw four more circles as shown, for a total of twelve. (It is okay if the new circles get cut off at the left and right edges of the paper.)  
  6. Draw line segments connecting all of the intersections. You will draw twenty triangles. Mark eleven tabs with a T, as shown. Carefully cut out around the white area--the twenty triangles and eleven tabs.

7. To make the largest possible icosahedron out of one sheet of paper, place it as shown so that your triangles and tabs still fit on the paper but unneeded portions of the circles get cut off.

 
 

Now fold, crease, decorate, and glue your icosahedron, following the same hints given on the tetrahedron page.

Your icosahedron is complete! Now would you like to make an icosahedron that is twice as big, using two sheets of paper?
Click here to make a big icosahedron!

 
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copyright 2000, 2001 by Wendy Petti of Math Cats