Multiple choice

The diameters of two right circular cones are equal. If their slant heights are in the ratio 3 : 2, then what is the ratio of their curved surface area?

  1. $9 : 4$
  2. $3 : 2$
  3. $3 : 3$
  4. $2 : 3$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Curved surface area of a cone = πrl where r is radius and l is slant height. If diameters are equal, radii are equal (r₁ = r₂). Given slant heights l₁ : l₂ = 3 : 2, the CSA ratio = πr(3) : πr(2) = 3 : 2. The radius cancels out, leaving the slant height ratio.