SOLUTION: Find the missing variable for a cone. r=9 L=? SA=622.04 Equation for SA=PIr^2+PIrL This is what I tried: 622.04=PI(9^2)+PI(9)(L) 622.04=PI(81)+PI(9)(L) 622.04=254.4690049+2

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Question 846130: Find the missing variable for a cone.
r=9
L=?
SA=622.04
Equation for SA=PIr^2+PIrL
This is what I tried:
622.04=PI(9^2)+PI(9)(L)
622.04=PI(81)+PI(9)(L)
622.04=254.4690049+28.2733388(L)
622.04=282.7433388(L)
622.04/282.7433388=L
L=2.20001608 which was incorrect, because when I plug 2.2 into the equation I do not get 622.04
Found 3 solutions by Fombitz, richwmiller, ewatrrr:
Answer by Fombitz(32388)   (Show Source): You can put this solution on YOUR website!

Now subtract 254.47 from both sides.
You added the right hand side together.
You really don't need that many decimal places either. 2 is plenty.
Answer by richwmiller(17219)   (Show Source): You can put this solution on YOUR website!
You messed up here
622.04=254.4690049+28.2733388(L)
622.04=282.7433388(L)
from here you can get
622.04=254.4690049+28.2733388(L)
L = 13.0006
using 3.14 for pi
622.04 = 3.14×81+3.14×9L
622.04 = 28.26L+254.34
367.7=28.26L
L = 13.0113
Answer by ewatrrr(24785)   (Show Source): You can put this solution on YOUR website!
 

Hi,



r=9

L=?

SA=622.04

SA=   Using 



  (198.1 - 81)/9 = L = 13.0113

CHECKING our answer***

SA=  = 

Wish You the Best in your Studies.



 

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