







Euler's polyhedron formula 
20160520 

From Antonia: why does not cylinders follow Euler's polyhedron formula ( VE+F=2) ??
if a cylinder has 3 faces, 2 edges and 0 vertices it doesn't follow Euler's formula??? Answered by Penny Nom. 





Polyhedra and polygons 
20100426 

From Brandon: What is the difference between a polyhedra and a polygon? Answered by Penny Nom. 





The inradius of an icosahedron 
20100121 

From fnavroth: Suppose you have an equilateral triangle.
The area of the triangle is exactly 1200 square centimetres.
Now suppose you have twenty of those triangles.
It's possible to assemble those twenty triangles into a closed
threedimensional shape, a regular polyhedron.
What would be the volume, in cubic centimetres, of the largest sphere
that could fit inside the shape? Answered by Chris Fisher. 





A polyhedron 
20090310 

From Mollie: Hi, my name is Mollie and I'm in 5th grade. Here's the math problem I have for homework tonight:
"Larissa made a model of a polyhedron using 8 pieces of clay for the vertices and 18 straws for the edges. What type of
polyhedron did Larissa make?"
Thanks. Answered by Penny Nom. 





Symmetries of a polyhedron 
20090302 

From Vincent: I want to ask is there a formula to find out the number of axes of rotation & plane
of reflection of a 3D figure, like pentagon, pyramid? Answered by Chris Fisher. 





Regular polyhedra 
20020607 

From Sandra: The other day a colleague and I were talking about polyhedra. Is regular a term applied to polyhedra or just polygons? If so, then what would define a regular polyhedron? Would it mean all faces are regular or would it mean that all faces are identical and regular? That is, could a pyramid with equilateral triangles for lateral faces and a square base be considered regular or must the base also be an equilateral triangle? Answered by Chris Fisher. 





Euler's Formula 
20001111 

From Denise Roberts: I'm trying to design a unit (possibly involving a Webquest) on Polyhedra and I cannot find a formula I once used. The formula involved the number of vertices (V), edges (E), and faces (F) of the polyhedra. Answered by Walter Whiteley. 





Angles 
20000106 

From Rayna: I am doing a presentation report on angles which has to be fun and entertaining as well as educational. I am having problems locating resources on angles that give me ideas of fun entertaining projects. My lecture is to be about 20 minutes long infront of a class of 11th and 12th graders. Please Help if you can. Answered by Claude Tardif and Walter Whiteley. 

