Question

Find the surface area of a cylinder with a base diameter of 12cm and a height of 7cm.

Answer 1

I;m about to fill it out... you can stick around to see if my answer is right

Answer 2

yeah sure.. u solve it first..

Answer 3

849.84

Answer 4

489.84****

Answer 5

yup..:D

Answer 6

u r correct..:D

Answer 7

so is it 490?

Answer 8

490picm^3?

Answer 9

(i have to write my answer in terms of pi :p)

Answer 10

490 is after you multiply by pi

Answer 11

u have to write it in the terms of pi means that u are not suppose to solve pi in the question
and total surface area of cylinder = 2 pi r ( h+r)
and diamter = 2 (radius) = 12
=> radius = 6 cm
and height given = 7 cm

so u would get
12 pi ( 13) = 156 pi cm^2

Answer 12

redo the calculation but do not multiply out by pi (leave the pi as is)

Answer 13

yeah @phi .. i agree with u..

Answer 14

I'm not solving pi in the equation (no more than I have to do being 2*pi*r^2 + 2*pi*r*h). I just have to write it in pi being _____ (my answer) * pi * cm^2

Answer 15

or, because you used pi= 3.14 , undo the multiply by calculation 489.84/3.14

Answer 16

so, it's 156*pi*cm^2?

Answer 17

yeah,, !!
but have you understood why is it so ?

Answer 18

No lol... The equation I'm using is 2πr² + 2πrh

Answer 19

in which i got 489.84

Answer 20

yeah the same was used by me.
the only difference is that i didn't solve for pi ( π)
and to make the calculations easy i took
2πr common..

Answer 21

thanks but i still dont understand what it means in term of pi XD i did the equation correctly...
whenever it says "write your answer in terms of pi" do i just divide my final answer by 3.14?

Answer 22

in terms of pi.. means that you are not supposed to solve for pi's value... just leave the pi as it is... in the answer...

Answer 23

i mean just leave it as it is...

Answer 24

don't solve for it..

Answer 25

so, i solve the equation WITHOUT multiplying by pi?

Answer 26

yeah...

Answer 27

what you did was figure out
2πr² + 2πrh with r= 6
where you used pi=3.14

but you could have done this: factor out the pi
(2r² + 2rh)π
now just compute the stuff inside the parens. Leave the pi as is

Answer 28

ohhh. so i dont solve for pi- okay. i think i get it now. sorry guys xD

Answer 29

the reason people want the answer in terms of pi is if you multiply it out, you have to choose a value for pi (for example 3.14) but pi is not *exactly* 3.14 so your answer is off.
If you leave the pi in, whoever wants the number can choose how accurately then need pi to be for their problem.

Answer 30

Here is a more accurate estimate of pi
3.14159265358979323846264338327950288419716939937510582097

Answer 31

i get it now :)