Question

Find the surface area of the cone

Answer 1

@amistre64 can you help me?

Answer 2

Equation for the area of the cone is something you have to memorize for the test.

Answer 3

I have it memorized and I've tried it but I keep getting 257. Idk if that's right or not

Answer 4

Did you add the \(\pi r^2\) area of the flat part?

Answer 5

I think the equation is \( \displaystyle A_{\mbox{cone}}=\frac{\pi r}{2}\sqrt{h^2+r^2}\) for the side.

Answer 6

Nah, its \(\displaystyle A_{\mbox{cone}}={\pi r}{}\sqrt{h^2+r^2}\)

Answer 7

So it would be 216.96?

Answer 8

\[r=4, \quad l=16\\
\mbox{There is no height so you can use the side length l}\\
A=\pi 4\times16+\pi 4^2, \qquad \pi4^2 \mbox{ is the flat bottom}
\]

Answer 9

So 100.48?

Answer 10

I got 251.2

Answer 11

Never mind that's what I got! I forgot to multiply by 16 haha

Answer 12

Great, it must be right then. There is this equation for the full area of the cone: \(A_{\mbox{cone}}=\pi r(r+l)\), should give the exact same result.

Answer 13

I hope so! Haha, thank you so much!!! :)

Answer 14

You are welcome.