Understanding different types of angles and that angles in a triangle sum to 180° can be helpful when classifying a triangle. Recognising line symmetry and rotational symmetry will also help.

Some students will say it’s not a triangle. Come back to the three connected sides idea. Continue making the triangle different shapes and size so that the student see a variety. Triangles examples: ...

The hexagon is then folded as shown. The figure can be flexed to show six different faces. If you have made the folds properly, the triangles on one visible face of the hexagon are all numbered 1 ...

Big Idea – We can describe, measure, and compare spatial relationships. to build on students' knowledge of triangle and develop students' reasoning with properties of different classes of triangles to ...