A right triangle with sides 3 cm, 4 cm and 5 cm is rotated the side of 3 cm to form a cone. The volume of the cone so formed is:
Aptitude
Volume and Surface Area
Difficulty: Easy
Choose an option
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A12π cm^3
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B16π cm^3
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C24π cm^3
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D32π cm^3
Answer
Correct Answer: 16π cm^3
Explanation
Problem Restatement
Rotating a right triangle about one leg forms a right circular cone: the axis (height) is the leg of rotation and the radius is the other leg.
Given data
- Right triangle sides: 3 cm, 4 cm, 5 cm (hypotenuse = 5 cm)
- Rotation about the side of 3 cm
Concept / Approach
Here, height h = 3 cm (axis of rotation) and radius r = 4 cm (the other perpendicular leg). The slant height (5 cm) is not needed for volume.
Step-by-step calculation
Cone volume V = (1/3)πr^2h= (1/3)π(4^2)(3) = (1/3)π × 16 × 3 = 16π cm^3
Final Answer
Volume of the cone = 16π cm^3.