If the radius and the slant height of this right circular cone are each multiplied by 4, by what factor is the surface area multiplied?

16

Step-by-step explanation:

Total surface area of a cone T1 = πr(r+l)

If the radius and the slant height of this right circular cone are each multiplied by 4, the new surface area will be expressed as;

T1 = π4r(4r+4l)

T2 = 16πr(r+l)

Taking the ratio of both total area

T1/T2 = πr(r+l)/16πr(r+l)

T1/T2 = 1/16

16T1 = T2

T2 = 16 T1

Hence the total surface area is multiplied by a factor of 16