Question

a cone of radius 12cm and hight 20cm it cut from the top 3cm and value of parallel to the base the remaining part becomes a frustom of cone. find the ratio of volume of the cone removed and volume of the frustom of the cone​

Answer 1

Step-by-step explanation:

Given, r

1

=12cm,h

1

=20cm,r

2

=3cm,h

2

=?

We know,

r

2

r

1

=

h

2

h

1

∴

3

12

=

h

2

20

∴h

2

=

12

3×20

=5cm

∴ The cut to be made at 5cm from the vertex.

Volume of the frustum=

3

1

πh(r

1

2

+r

2

2

+r

1

r

2

)

=

3

1

×

7

22

×15(12

2

+3

2

+12×3)=

7

110

×(144+9+36)

=

7

110

×189=2,970

∴Volume of the frustum=2,970cm

3

.

solution