I asked this question yesterday, and I'm trying to understand it since I got the wrong answer - please explain:

Question

You need to make a soda can with a volume of 29 cubic inches.

Find the surface area. calculate the following:
a) How much material is needed if the can's radius is 1 inch?

I figured it this way:

Let the height be h
volume = π r²•h
29 = π (1²) • h
h = 29/π

So πr² • 2 + 2π • 29/π

2π + 58 = 64.28 in²

but person who helps me gets it this way:

Let the height be h
volume = π r²h
π (1²)h = 29
h = π /29

the surface area are
= 2 π r²+ 2 π rh
= 2 π (1) + 2 π (1)( π /29)
= 6.96 in²

Can anyone help me and tell me which is correct? I think the problem may
be that I get the volume 29/╥

intead of ╥/29

Answer 1

π (1²)h = 29

If you divide both sides by π, you get:

h = 29/π