Maths · Circle, conic sections: A standard form of equations of a circle, the general form of the equation of a circle, its radius and centre

The diameter of a right circular cylinder is decreased by 10\%. The volume of cy

The diameter of a right circular cylinder is decreased by 10\%. The volume of cylinder remains the same then the percentage increase in height is:

  • A. 20\%
  • B. 23.45\%
  • C. 5\%
  • D. 20.5\%

Step-by-step solution

Let original radius = r, height = h. Diameter decreased by 10% means radius becomes 0.9r. Volume remains same: πr²h = π(0.9r)²h' → h' = h/0.81 = (100/81)h. Percentage increase in height = (h'/h - 1)×100% = (100/81 - 1)×100% = (19/81)×100% ≈ 23.45679% ≈ 23.45%.
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