Better Lesson
Better Lesson: Making New Shapes With Shapes
My first graders have been studying the defining attributes of 2D shapes. They are going to love using toothpicks and marshmallows to present their knowledge of 2D and create 3D shapes.
National Council of Teachers of Mathematics
Nctm: Illuminations: Geometric Solids
An interactive game to find number of edges, surfaces and vertices of different geometric shapes.
Science Struck
Science Struck: A Comprehensive Printable List of Geometry Formulas
Provides a list of area and perimeter formulas for two-dimensional shapes and volume and surface area formulas for three-dimensional solids.
CK-12 Foundation
Ck 12: Interactive Geometry: 9.5 Modeling in Three Dimensions
Explore connections between a 2-dimensional net and a 3-dimensional box. Later in this section, use equations with variables to solve real world problems that use 2 and 3-dimensional objects.