Question

find the total surface area of a cone which has slant height 4l &diameter 4r

Answer 1

slant height of a cone = 4l
radius = 4r
total surface area of the cone = πr(r+l)

= π*4r(4r+4l)
=π*4*4*r(r+l)
=16πr(r+l) squre units