Annenberg Foundation
Geometry 3D Shapes: Platonic Solids
From polyhedrons to platonic solids, here is a lesson that will have your classes talking! As an introduction to platonic solids, scholars cut and fold nets to create the three-dimensional solids. They use an interactive component to...
National Council of Teachers of Mathematics
The Math Forum: Ask Dr. Math: Building Two Column Proofs
Use this site to find details of how to construct a two column proof. Dr. Math responds to a question posed by a student and details the reasons for the order of steps and shows two different ways to do the same proof.
PBS
Pbs Learning Media: Two Sightings, Different Information
Jackie and Matt are looking at the same object along two different lines, in this video segment from Cyberchase.