Question

salo tum ek question ka answer do the radius of the base of a right circular cone of semi vertical angle alpha is r find the volume of cone​

Answer 1

Step-by-step explanation:

Let height of cone be 'h', then in △OBA

tanα=

OB

OA

=

h

r

⇒h=

tanα

r

=rcotα

Volume =

3

1

πr

2

h=

3

1

πr

2

.rcotα=

3

1

πr

3

cotα

CSA=πrl=πr

r

2

+h

2

=πr=

r

2

+(rcotα)

2

=πr

r

2

+r

2

cot

2

α

=πr

r

2

(1+cot

2

α)

=πr

r

2

csc

2

α

=πr.rcscα=πr

2

cscα