Geometry is one of the practical section of Mathematics which involves various shapes and sizes of different figures and their properties. **Geometry** can be divided into two types: **plane** and **solid** **geometry**. Plane geometry deals with flat shapes like lines, curves, polygons, etc., that can be drawn on a piece of paper. On the other hand, solid geometry is about the objects of three-dimensional shapes such as cylinders, cubes, spheres, etc. Here we will discuss a few fundamental elements of the solid geometry – the three-dimensional shapes.

#### What are Three-Dimensional Shapes?

The shapes which can be measured in 3 directions are called three-dimensional shapes. These shapes are also called solid shapes. Length, width, and height (or depth or thickness) are the three measurements of the three-dimensional shapes. They are different from 2D shapes because they have thickness. A number of examples can be found in everyday life. Some of them are:

The Rubik’s Cube is an example of a cube, the drum is a cylinder, the birthday cap is a cone and the orange is a sphere.

#### Faces, Edges **and Vertices**

Three-dimensional shapes have many attributes such as faces, edges and vertices. The flat surfaces of the 3D shapes are called the faces. The line segment where two faces meet is called an edge. A vertex is a point where 3 edges meet.

Let us consider a few shapes to learn about them.

#### Cube

- All edges are equal
- 8 vertices
- 12 edges
- 6 faces.

#### Cuboid

- 8 vertices
- 12 edges
- 6 faces

#### Prism

- 6 vertices
- 9 edges
- 5 faces – 2 triangles and 3 rectangles

#### Square Pyramid

- 5 vertices
- 8 edges
- 5 faces

#### Cylinder

- No vertex
- 2 edges
- 2 flat faces – circles
- 1 curved face

#### Cone

- 1 vertex
- 1 edge
- 1 flat face – circle
- 1 curved face

#### Sphere

- No vertex
- No edges
- 1 curved face

*Learn more about the three-dimensional shapes and solve NCERT problems with solutions by downloading Byju’s – The Learning App.*

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