# volume of cone formula

## CONES:

If one end of a line is rotated about a second fixed line while keeping the line's other end fixed, then a cone is formed.  The point about which the line is rotated is called the vertex and the base of the cone is a circle.

A cone is said to be right when the vertex is directly above the centre of the base.

Consider a cone in which base radius = r, height = h and slant height,

.

Then, we have

• Volume of the cone h cubic units

• Curved surface area of the cone sq units

• Total surface area of the cone

= (curved surface area) + (area of the base)

sq units

### SOLVED EXAMPLES

question The height of a cone is 24 cm and the diameter of its base is 14 cm. Find the slant height, volume, area of curved surface and the total surface area of the cone.

Solution:   Here, h = 24 cm and r = 7 cm.

Let the slant height be I cm. Then,

∴slant height = l cm = 25 cm.

Volume of the cone

Curved surface area of the cone

Total surface area of the cone =

= 704 cm2

## CBSE NCERT Solutions for Class 8 Maths

### Notes,worksheet and solved question for Maths class 8

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