What is the surface area of a cone with a 6 in. diameter and a length (slant height) of 8 in? A. 11in^2
B. 75in^2
C. 104in^2
D. 179in^2

The formula of a surface area of a cone:

SA=pi rl+\pi r^2SA=pirl+πr

2

r - radius

l - slant height

We have the diameter d = 6 in and a slant height l = 8 in.

d=2r\to r=6in:2=3ind=2r→r=6in:2=3in

Substitute:

SA=\pi(3)(8)+\pi(3^2)=24\pi+9\pi=\boxed{33\pi\ in^2}SA=π(3)(8)+π(3

2

)=24π+9π=

33π in

2