Question

Find the total surface area of a cone whose radius is R/2 Slant height = 12 (l)​

Answer 1

Answer:

Substituting these values in the formula of calculating the total surface area of the cone, the total surface area of the given cone is =πr2(r2+2l). Simplifying the above expression, the total surface area of the cone is =πr2(r2+2l)=πr(r4+2l2)=πr(r4+l).

Answer 2

Simplifying the above expression, the total surface area of the cone is =πr2(r2+2l)=πr(r4+2l2)=πr(r4+l). Hence, the total surface area of the cone whose radius is r2 and slant height is 2l is πr(r4+l), which is option (b).