Question

What is the surface area of a cone when the slant height is 6 mm and the diameter is 4 mm?

Answer 1

Diameter of cone = d = 4mm
So,
Radius of cone = r = 2mm
Slant Height = l = 6mm
Surface Area = A = ? 

The formula for the surface area of cone is:

$A= \pi r(r+l)$

Using the values, we get:

$A= \pi (2)(2+6)=16 \pi$ mm²

Therefore, the surface area of the cone with diameter 4mm and slant height of 6mm will be 16π mm²