Multiple choice

The radius and the height of a cone are in the ratio 4:3. The ratio of the curved surface area and total surface area of the cone is

  1. 5 : 9

  2. 3 : 7

  3. 5 : 4

  4. 16 : 9
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Let r=4x, h=3x. Slant height l = √(16x² + 9x²) = 5x. Curved surface area = πrl = π(4x)(5x) = 20πx². Total surface area = πr(l+r) = π(4x)(5x+4x) = 36πx². Ratio = 20:36 = 5:9.

Keep practicing — related questions