3-D Figures (Pyramids and Curved Surface)

We finished our note taking on 3-d figure nets today.  It meant more cutting, folding, and taping, but the kids enjoyed it!  We began by determining the critical attributes of pyramid nets.  These nets will have multiple triangles and a single polygon base.

One of our nets was a pentagonal pyramid (like the one above).  We knew this net would become a pyramid due to the triangles, and we new to name it a pentagonal pyramid due to the pentagon base.  We worked with 5 different pyramid nets finding each net's number of faces, number of edges, and number of vertices.  We also looked for patterns to help us find the edges and vertices since looking at a picture can be deceiving.  For example, if you look at the pentagonal pyramid net, you might think that the solid figure itself might have 17 edges (by counting each black line) when it only has 10 as seen on the model, not the net.  You  might also conclude that the figure has 10 vertices (counting every point you see) when it only has 6, as seen on the model, not the net.

We then moved to working with nets for curved surface 3-d figures.  This was very easy for the classes.  The only point of contention was whether or not a cone and cylinder have edges.  After looking at different resources, we concluded that a cone has 1 curved edge (0 straight edges) and a cylinder has 2 curved edges (0 straight edges).

Fun way to end the week!