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: differing orientations and sizes 4. Together ...

have three sides, therefore they have three angles. Interior angles in a triangle sum to a half turn (180˚). Quadrilaterals close quadrilateralA polygon with four straight sides. have four sides ...

The ancient Greek mathematician Euclid proved in his Elements of Geometry that there are only five Platonic solids – the regular tetrahedron (four sides that are equilateral triangles), the cube (six ...