Exploratorium
Angle Hunting
Do angles change with distance? Using a previously made tool, individuals find and measure angles on a playground. They observe that angles are the same measure regardless of the distance at which they're measured.
Illustrative Mathematics
Are These Right?
Is that a right triangle or a wrong triangle? Young mathematicians look at eleven different shapes and use a measuring tool of their choice to determine which triangles have right angles. Consider cutting out sets of the shapes to...