Question

7 . A right triangle ABC with sides 5cm,12cm,and 13cm is revolved about the side 12cm.Find the volume of the solid so obtained.8 . If the triangle ABC in the question 7above is revolved about the side 5cm,then Find the volume of the solid so obtained. Find also the ratio of the volume of the 2solids obtained in Question 7and 8.​

Answer 1

Answer:

When the triangle is revolved around the side 12cm, the solid obtained is a cone with height 12cm, radius 5cm and slant height 13cm

Volume of cone =

3

1

πr

2

h

where, r is the radius of the base of the cone and h is the height.

Hence, volume of this cone =

3

1

×π×5

2

×12=100πcm

3

When the triangle is revolved around the side 5cm, the solid obtained is a cone with height 5cm, radius 12cm and slant height 13cm

Hence, volume of this cone =

3

1

×π×12

2

×5=240πcm

3

Ratio of the volumes 100π:240π=5:12