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:
[tex]A= \pi r(r+l)[/tex]
Using the values, we get:
[tex]A= \pi (2)(2+6)=16 \pi [/tex] mm²
Therefore, the surface area of the cone with diameter 4mm and slant height of 6mm will be 16π mm²