Question

So, I'm doing Surface Area of a Cone,
L= 7in
R= 8in
I calculated B (pi * 8^2) so B (also known as Area of Circle) = 200.96
Now I'm working on SA and a little confused,
SA=B+LA
=pi*8^2 + pi*8*7=11,429.6
but the next step in my equation says I should have 2 pi's (EXAMPLE; =pi (4)^2 + pi(4)(10) = 16pi + 40pi )
So could someone walk me through it? Thank you.

Answer 1

I'm assuming that L is the slant height, so your formula for total area is correct
pi R^2 + pi RL

I have no idea what the "next step" is supposed to be, since you already have the total area. Is 4 the radius of some other cone, with slant height 10?
If so, I suppose there must be some connection between the two cones ...

What have you left out?

Answer 2

I may not be understanding it, these are my sources for the formulas I'm using;
ht tps://sciencing.com/ calculate-base-cone-8178426.html (space in url)
ht tps://www.youtube.com/ watch?v=pkWED4nyCHA&list=PL_Z-HL5bvIMtchPQhzT731CS9U3010h2E&index=2&t=0s (space in url)
@1:00 He writes 2 sums with the pi symbol, is this specific to his problem ?
The 4 radius was the example he used, it isn't specific to my work, only Slant = 7 & Radius = 8. So 11,429.6 is already the surface area?
*phew.* All this math gets confusing & I try to over complicate it,.