The curved surface area of a cone is 20cm^2 and its slant height and radius are consecutive natural no.s then find its volume
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Answer:
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Step-by-step explanation:
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Answered by
0
Answer:
16 π cm³
Step-by-step explanation:
There is correction in question:- The curved surface area of a cone is 20π
Let the slant height be x+1 & radius be x.
Now, curved surface area of a cone = 20π
∴ π × radius × slant height = 20π
∴ π. x+1. x = 20π
∴ (x² + x) = 20
∴ x² + x - 20 = 0
∴ x² + 5x - 4x -20 = 0
∴ x(x + 5) -4 (x +5) = 0
∴ (x - 4) (x + 5) = 0
Therefore x = 4 or -5
x = -5 is invalid.
So, x = 4
So, Radius = 4, Slant Height = 5
Since Slant Height = 5, Height = √(5² - 4²) = 3
Volume = 1/3 πr²h = 1/3. π. 4².3 = 16 π cm³
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