2017 · Q72
The vertical angle of a right circular cone is π/2 and the slant height is √(2) r cm. What is the volume of the cone in cubic cm ?
Elementary MathematicsMensuration
- Aπ r³
- B9π r³
- C(π r³)/3
- D3π r³
Explanation
Semi-vertical angle = π/4, so radius = height (tan π/4 = 1). Slant height √(r²+h²) = r√2 = √2·r is consistent with the data. Volume = (1/3)πr²h = πr³/3. Hence option (C) (πr³)/3.