Correct Answer - Option 1 : 1 : 252

**Given**

Ratio of radii of two cones = 1 : 36

Ratio of slant height of two cones = 1 : 7

**Formula used **

Curved surface area of cone = πrl

Where r and l are radius and slant height of a cone respectively.

**Calculation**

CSA_{1}/CSA_{2}= πRL/πrl

Where R and r radius of first and second cone

CSA1/CSA2 = (1/36) × (1/7)

CSA1/CSA2 = 1 : 252

**∴ The ratio of the two curved surface area of a cone is 1 : 252.**