The slant height of a cone is augmented by 20%, while the base radius remains the same. What is the percentage increase in the curved surface area of the cone?
Show answer & explanation
Correct answer: A
Explanation
Slant height increased by 20%, radius same
according to formula
Curved surface area = πrl
Old area = πrl
New area = πr(1.2l) = 1.2πrl
Increase = (1.2 − 1) × 100 = 20%