I need help! my problem is in the comments.

Question

rebeccaxhawaii · Answer

whats up?

anonymous · Answer

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anonymous · Answer

close as i can get it but i need to find the volume

anonymous · Answer

in terms of pi

jim_thompson5910 · Answer

volume of a cylinder

$$\Large V = \pi*r^2*h$$

r = radius
h = height

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anonymous · Answer

it 9cm all the way across and i have to get it in terms of pi thats whats throwing me off

jim_thompson5910 · Answer

oh right, 9 is the diameter. My bad

d = 9 is the diameter
r = d/2 = 9/2 = 4.5 is the radius

jim_thompson5910 · Answer

ignore the `pi` in the formula I wrote. We'll throw it in later

focus on the `r^2*h`

what is `r^2*h` equal to when r = 4.5 and h = 19 ?

anonymous · Answer

384.75

jim_thompson5910 · Answer

so the volume is `384.75pi`

jim_thompson5910 · Answer

`in terms of pi` means that you have a `pi` tacked on as if it were like a variable (like x in 3x)

anonymous · Answer

ok i just realized i put volume instead of surface area sorry

anonymous · Answer

i just figured it out nevermind sorry i skip steps and said half of 9 is 3 for some reason

jim_thompson5910 · Answer

You'll use this formula then
$$\Large SA = \pi*\left(2*r*h + 2*r^2\right)$$
which is equivalent to this form (I distributed the pi through)
$$\Large SA = 2\pi*r*h + 2\pi*r^2$$

jim_thompson5910 · Answer

ok I'm glad you figured it out

anonymous · Answer

lol thanks :)

jim_thompson5910 · Answer

no problem