If the triangle ABC in the Question 7 above is revolved about the side 5 cm, then find the volume of the solid so obtained. Find also the ratio of the volumes of the two solids obtained in Questions 7 and 8
Solution:
Since the triangle is revolved about the side 5 cm, a solid cone if formed with a height of 5 cm and radius of the base of 12 cm.
Volume of a cone having radius 'r' and height 'h' = 1/3πr²h
Radius of the cone, r =12cm
Height of the cone, h = 5cm
Volume of the cone = 1/3πr²h
= (1/3) × π × 12cm × 12cm × 5cm
= 240π cm³
Volume of the cone in question 7 = 100π cm
Ratio = Volume of the cone in question 7 : Volume of the cone in question 8
= 100π : 240π
= 5 :12
The volume of the cone is 240π cm³ and the required ratio is 5 :12
☛ Check: NCERT Solutions for Class 9 Maths Chapter 13
Video Solution:
If the triangle ABC in the Question 7 above is revolved about the side 5 cm, then find the volume of the solid so obtained. Find also the ratio of the volumes of the two solids obtained in Questions 7 and 8.
NCERT Solutions for Class 9 Maths Chapter 13 Exercise 13.7 Question 8
Summary:
It is given that the triangle ABC in the question above is revolved about the side 5 cm. We have found that the volume of the cone is 240π cm³ and the required ratio is 5 : 12.
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