A pyramid is named by the shape of its ‘base’. A pyramid with a triangular base is a triangle-based pyramid. A tetrahedron is a triangular pyramid with all equilateral triangle faces.

These shapes are all regular polygons. A regular triangle is called an equilateral triangle. A regular quadrilateral is called a square. Irregular polygons are shapes that have sides and angles of ...

Dudeney's question concerned transforming an equilateral triangle into a square by cutting ... applying their method to other geometric shapes, promising new advances in this field.

Properties of symmetry: - Students may notice symmetry in the isosceles and equilateral triangles and ... While initially very similar looking, these triangles behave very differently under dragging. ...