Question

The CSA of a cone is 165 cm². If its slant height is 10 cm, Then find the diameter of base of the cone :
1. 9.6 cm
2. 10.5 cm
3. 8.5 cm
4. 12.4 cm

Answer 1

Correct Answer - Option 2 : 10.5 cm

Given :-

The CSA of a cone = 165 cm²

Slant height = 10 cm

Concept :-

Curved/Lateral surface area of cone = πRl

Where, l = Slant height, R = Base radius of cone, π = (22/7)

Diameter = 2 × Radius

Calculation :-

⇒ 165 = (22/7) × R × 10

⇒ R = (165 × 7)/(22 × 10)

⇒ R = (21/4)

Now, 

⇒ Diameter of base of the cone = 2 × (21/4) = 10.5 cm

∴ Diameter of base of the cone = 10.5 cm

CSA = Curved Surface Area.