Volume

Volume is a mathematical quantity that shows the amount of three-dimensional space occupied by an object or a closed surface. Volume is also termed as capacity, sometimes. For example, the amount of water a cylindrical jar can occupy is measured by its volume. Check volume of cylinder here.

Different shapes have different volumes. In 3d geometry, we have studied the various shapes and solids such as cube, cuboid, cylinder, cone, etc., that are defined in three dimensions. For all these shapes, we are going to learn to find the volume.

Check the volumes of different shapes here:

Unit

Volume of a solid is measured in cubic units. For example, if dimensions are given in meters, then the volume will be in cubic meters. This is the standard unit of volume in the International System of Units (SI). Similarly, other units of volume are: cubic centimeters, cubic foot, cubic inches, etc.

Example: If a cuboid has dimensions of 10cm x 3cm x 5cm, then find its volume.

Sol: Volume of cuboid = length x width x height

V = 10cm x 3cm x 5cm

V = 150 cubic centimeters

Hence, we can see here the unit of volume of cuboid is measured in cubic centimeters.

Volume of liquid

Basically, the volume of a liquid is measured in liters, where 1 liter is equal to 1000 cubic centimeters.

1 liter = 1000 cubic centimeters = 0.001 cubic meters

Hence,

1 cubic meters = 1000 liters

Also, to measure the volume of a small amount of liquid, we use milliliters.

1 milliliters = 0.001 liter = 1 cubic centimeters

Volume of liquid is also commonly measured in gallons.

1 liter = 0.264172 US liquid gallon

Volume Formulas

The formula to calculate the volume of a solid in a three-dimensional space, is to find the product of dimensions. Basically, the volume is equal to the product of area and height of shape.

Volume = Area x Height

For shapes having flat surfaces such as cube and cuboid, it is easy to find the volume. But for curved shapes like cone, cylinder and sphere, we have to consider the dimensions of its curved surface as well, such as radius or diameter.

Let us check the formulas for all the shapes.

Volume of Shapes

Name of geometrical shape

Volume formula

Cube

V = a3, where a is the edge-length of cube

Cuboid

V = length x width x height

Cone

V = ⅓ πr²h

Where r is the radius and h is the height of cone

Cylinder

V = πr²h,

Where r is the radius and h is the height of cylinder

Sphere

V = 4/3 πr3,

Where r is the radius of sphere

Volume of other shapes

Volume of Frustum

πh/3 (R2+r2+Rr)

Where ‘R’ and ‘r’ are radius of base and top of frustum

Volume of Prism

Base Area x Height

Volume of Pyramid

⅓ (Area of base) (Height)

Volume of Hemisphere

⅔ (πr3)

Where r is the radius

Interesting Facts:

  • The cube has all its sides equal, therefore, the volume will be equal to the cube of its side-length.
  • If the radius and height of a cone and a cylinder are the same, then volume of cone is equal to one-third of volume of cylinder.
  • The formula of volume of cuboid and rectangular prism is the same.
  • The volume of the prism depends on the shape of its base. For example, if the base is square, then the volume will be (side2 x height).

Solved Examples

Q.1: Find the volume of a cube if its side-length is equal to 4 cm.

Solution: Given, length of cube = 4cm

As we know,

Volume of cube = Side3

Therefore,

Volume of cube with 4cm length = 43 (cm)3

Volume = 64 cm3

Q.2: What is the volume of cone if radius is 2cm and height is 5cm.

Solution: Given, radius of circular base of cone = 2cm

Height of cone = 5cm

As we know,

Volume of cone = ⅓ πr2h

Volume = ⅓ π (2)2 (5)

Volume = ⅓ x 22/7 x 4 x 5

Volume = 20.93 cu.cm.

Practice Questions

  1. Find the volume of spherical shape with diameter equal to 12cm.
  2. A gas cylinder if flattened on top and bottom, to get two parallel circular faces on either side of the curved surface. Find the volume if radius of circular bases is 10 cm and height of cylinder is 50 cm.

Frequently Asked Questions on volume

What is volume?

Volume is a three dimensional quantity that is used to measure the capacity of solid shape. It means, the amount of three dimensional space that a closed figure can occupy is measured by its volume.

What is the formula for volume?

Unlike area, where two dimensions are multiplied to find the region covered by a shape, volume is measured by multiplying area of the shape with its third dimension. For example, if the area of the rectangle is length x breadth, then the volume of cuboid formed by elongating the dimensions of the rectangle in space, is equal to length x breadth x height.

What is the unit of volume?

In Maths, volume is measured in cubic units, such as cubic meters, cubic centimeters, cubic millimeters, etc.

The volume of liquid is usually measured in liters and gallons.

Is the volume of cube and cuboid the same?

A cube has all its faces in square shape and a cuboid has rectangular faces. Therefore, the edge lengths of cube are equal to each other whereas for cuboid they are different. Hence, a cube and a cuboid cannot have the same volume.

What is the volume of a pyramid?

The volume of a pyramid is equal to the product of its area and its height.

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