Question

A solid cone of Radius 'R' and height '3R' is converted to another solid cone of base Radius '3R' .The change
in curved surface area

Answer 1

CSA-1 = πR(L1) = (√10) π R^2.........(i)

vol-1 = vol-2

=> (1/3)π × 3R × R^2 = (1/3)π × (3R)^2 × h

=> h = R/3

CSA-2 = π(3R)×(L2) = 3πR^2 √(3×3 + 1/9)

= (√82)π R^2.......…....…...................(ii)

change in CSA = CSA-2 - CSA-1

= (√82 - √10) π R^2 .....

....answer.....