3D objects Saturday, 17 November 2018

Pyramids Definition: A pyramid is a solid in which the cross-sectional area reduces to a point. In other words if the base was a polygon then of each side of the polygon would be a triangular face which all meet at a common vertex. vertex face face

5 8 5 1. square-based pyramid Properties Number of faces = Number of edges = Number of vertices = Has planes of symmetry Has rotational symmetry from a given axes. 5 8 5

Planes of symmetry

4 6 4 2. Tetrahedron Properties Number of faces = Number of edges = Number of vertices = Has planes of symmetry Has rotational symmetry from a given axes. 4 6 4

Planes of symmetry

2 3. Cone Properties Number of faces = Has planes of symmetry Has rotational symmetry from a given axes. 2

Planes of symmetry

Spheres Definition: A sphere is not like any prism or pyramid and so is in a category all of its own. A sphere is a perfectly round shape. Properties Has an infinite number of planes of symmetry Has rotational symmetry from a given axes.