volume & circumference

Becky4paws

Junior Member
Joined
Feb 15, 2006
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63
Given that a cylinder of a radius r and height h has volume V = pi (r^2)(h) and a circle of radius r has area A = pi (r^2) and circumference of C =2(pi)(r).

A soda can haolds 12 fluid ounces (approx. 6.89(pi) cubic inches). Express the surface area of teh can as a function of its radius.

I have solved for V below but don't feel comfortable with the answer:

V = pi(r^2)(h)
6.89pi = pi(r^2)(h)
6.89pi/pi(h) = r^2

If that is actually correct, I would continue by substituting that answer into A = pi(r^2), but I don't feel I am correct in the above answer.
 
I suspect that what they want is
SA = 2A + Ch =
2*pi*r²+2V/r
 
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