The two branches of Geometry are:

Plane Geometry - is all about shapes like lines, circles and triangles ... Shapes that can be drawn on a flat surface called a Plane (it is like on an endless piece of paper)

Solid Geometry - is the geometry of three-dimensional space, the kind of space we live in ...

Three Dimensions

It is called three-dimensional, or 3D because there are three dimensions: Width, depth and height.

There are two main types of solids, "Polyhedra", and "Non-Polyhedra":

Polyhedra

A polyhedron is a solid made of flat surfaces. Each surface is a polygon. Examples:

Platonic Solids

Prisms

Pyramids

Non-Polyhedra

Some solids have curved surfaces, or a mix of curved and flat surfaces (so they aren't polyhedra). Examples:

Sphere

Torus

Cylinder

Cone

Plane Geometry - is all about shapes like lines, circles and triangles ... Shapes that can be drawn on a flat surface called a Plane (it is like on an endless piece of paper)

Solid Geometry - is the geometry of three-dimensional space, the kind of space we live in ...

Three Dimensions

It is called three-dimensional, or 3D because there are three dimensions: Width, depth and height.

There are two main types of solids, "Polyhedra", and "Non-Polyhedra":

Polyhedra

A polyhedron is a solid made of flat surfaces. Each surface is a polygon. Examples:

Platonic Solids

Prisms

Pyramids

Non-Polyhedra

Some solids have curved surfaces, or a mix of curved and flat surfaces (so they aren't polyhedra). Examples:

Sphere

Torus

Cylinder

Cone