**First Glance **

Space is always a subject of wonder to all of us. In fact, the points of the space figures never lie in the same plane. The study of polyhedron, the cylinder, the cone and the sphere form an important part of the study of space figures.

There are space figures that have a flat surface called faces. These space figures are called polyhedrons/ Some examples of polyhedrons are cubes, prisms and pyramids. However, cylinders, cones, and spheres are not polyhedrons as they bear a curved surface and lack the flatness. Moreover, cylinders have two parallel, congruent bases too. A cone boasts a typical feature of having only one circular base along with a vertex that is not on the base. The sphere is another space figure that boasts a unique feature of having all points at an equal distance from the center.

**In Depth **

The space can only be described in terms of three dimensions. The three dimensions are length, width and height. The importance of a polyhedron can be known from the fact that three-dimensional geometry is used to describe buildings, tools or the creation of any kind of objects.

**Polyhedrons**

Polyhedrons are the three-dimensional polygons. The word polyhedrons has its origin in the Greek word â€œpolyâ€ meaning â€œmanyâ€ and â€œhedraâ€ meaning, â€œfacesâ€. As the Greeks were responsible for many geometric discoveries, so most of the geometric figures have Greek names.

**Rectangular or square prism**

The polyhedrons or the other space figures can well be related to the two-dimensional figure as well as you can create a rectangular or a square prism from vertical rectangle by moving it horizontally. Moreover, polyhedron is a body, boundary that comprises many planes in pieces. The diagonals of the polyhedrons are those, which joins two vertices, which are not placed on the same face. Moreover, if all the diagonals are placed inside the polyhedron then it is called a convex one.

**T****riangular prism**

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The other two-dimensional figure that can be used for relating the three dimensional figure is a vertical triangle which can be used to make a triangular prism by moving it horizontally. This type of prism has the feature of splitting sunlight into the colors of a rainbow.

**Cylinder**

You can also be aware about some figures which may not be polyhedrons but they also have a relation with a two-dimensional figures. The cylinders which can have two ways of construction. One is when a circle moves up in a straight line perpendicularly it creates a cylinder. It can also be created if a rectangle revolves around its axis about one of its sides. The cylindrical shape is very much common in our modern life in the form of pipes, columns, cans, musical instruments, and in many other applications.

**Cone**

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The cone is also generated from a two-dimennsional figure. It can be formed when a right angled triangle revolves about on one of its sides. The cone has a vertical height, which is the real height of the cone and a slant height which is the measure of the slanting height. Cone shapes are familiar to us because ice cream is served in this often.

**Sphere**

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Like all other space figures the sphere can also be created if a circle is twirled around one of its diameters. The diameter of a sphere is the line segment passing through the center of the sphere and having its end points on the sphere. The plane which contains the diameter of the sphere divides them into two equal parts and each part is called the hemisphere.

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Apart fom all these, there are also other space figures. Some of them even don’t have names till date while others have a name. One such attractive figure having a heavy name indeed is “rhombicosidodecahedron”. It is also claimed that it is more attractive than a 3-D figure. The figure is said to have equilateral triangles, squares, and regular pentagons for its surfaces. This proves that geometry is a like a vast universe which is still unexplored.

**Examples:**

- If you twirl a circle around its diameter, you get a sphere. A ball is an example of a sphere.
- When a right-angled triangle revolves about on one of its sides a cone is formed and the most common example of a conical shape is an ice-cream cone
- When a circle moves up in a straight line perpendicularly from its base it creates a cylinder. The common cylindrical shapes we notice in our everyday life objects are in water pipe segments and cans.
- A space figure with a single vertex is called a cone
- When a vertical triangle is moved horizontally on its base it forms a prism. These prisms can split sunlight into the colors of the rainbow.

**Test your knowledge – try our Space Figures Test.**