Display various triangular shapes and ask, "How do you know that these shapes are triangular?" The following properties of triangles should emerge from this discussion: three sides, three corners and angles, straight rather than
curved sides.
Distribute pattern blocks to each group of two to four students. Have students explore ways to make triangles with the patterning blocks.
Alternatively, you can use the Patch Tool for pattern blocks. This is an applet version of physical pattern blocks.
Have students share solutions with each other. As a class share any common findings and anything unique that students may have discovered.
Distribute and follow directions in the How Do You Build Triangles? Activity Sheet.
Have students work in pairs to give or write directions for building one of the triangles, then see if another pair of students can build it by following the directions.
Some possible solutions for the activity sheet include:
Have students compare their drawings with those of several classmates. What do they notice?
