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Question
The diameter of the base of a cone is 42 cm and its volume is 12936 cm3. Its height is
Options
28 cm
21 cm
35 cm
14 cm
Solution
28 cm
Let h be the height of the cone.
Diameter of the cone = 42 cm
Radius of the cone = 21 cm
Then, volume of the cone`= 1/3 pi"r"^2"h"`
`= 1/3xx22/7xx21xx21xx"h"`
= 22 × 21 × h
Therefore,
22 × 21 × h = 12936
`=> h = ((12936)/(22xx21))`
⇒ h = 28 cm
Hence, the height of the cone is 28 cm.
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