Question

Class 9
What is the total surface area of a cone if its radius is R/2 and length 2L?

Answer 1

Answer:

πr(l+r/4)πr(l+r/4)

Step-by-step explanation:

We have to calculate the total surface area of the cone whose radius is r2r2 and slant height is 2l2l.

We know that the total surface area of a cone with radius ‘r’ and slant height ‘l’ is πr(r+l)πr(r+l).

 



We know that the radius of the given cone is r2r2 and its slant height is 2l2l.

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)=πr2(r2+2l).

Simplifying the above expression, the total surface area of the cone is =πr2(r2+2l)=πr(r4+2l2)=πr(r4+l)=πr2(r2+2l)=πr(r4+2l2)=πr(r4+l).

Hence, the total surface area of the cone whose radius is r2r2 and slant height is 2l