Question

Find the height of a cylinder with a radius of 3.5 cm & surface area of 1000 cm. sq.
A)13.42
B)26.83
C)41.97
D)20.0

Answer 1

surface area of a cylinder is \[\LARGE SA = 4\pi r^2 + 2\pi rh\]
does that help?

Answer 2

i can explain further if you want....

Answer 3

Replace SA with 1000 and r with 3.5

Answer 4

Apparently you have to solve for h.

Answer 5

I DONT GET WHAT EITHER OF YOU ARE SYAING AT ALL & @lgbasallote : YOU HAVE TO FIND THE HEIGHT NOT THE SURFACE AREA

Answer 6

ahh yes...like i said you need only ask..

Answer 7

Yeah, we know the surface area and radius, we have to solve for h.

Answer 8

\( \color{Black}{\Rightarrow 1000 = 4\pi (3.5)^2 + 2\pi (3.5)h }\)
Solve for h, which is the only variable here

Answer 9

Use the following formula:
\[h = (SA - 4\pi r^2)/2\pi r\]

Answer 10

@waterineyes Solving for h in the equation is a better start.

Answer 11

now i shall provide you with some magic...

\[\large SA = 4\pi r^2 + 2\pi rh\]
\[\large SA - 4\pi r^2 = 2\pi r h\]
\[\large \frac{SA - 4\pi r^2}{2\pi r} = h\]
now can you solve for h?

Answer 12

you will simply substitute SA and r into the equation i provided ;)

Answer 13

^ good way to do so

Answer 14

\(\Huge \text{<tips cap>}\)
yw

Answer 15

ParthKohli, that is what you think but I don't...

Answer 16

@waterineyes unexplained definition isn't the right way, though lgba explained it well enough

Answer 17

Then writing the direct formula is also not an explanation my dear friend...

Answer 18

@lgbasallote : I DID THE FORMULA & GOT 4649.5393. WHICH IS NOT CORRECT

Answer 19

Thank you for the caps attack, but we don't need one.

Answer 20

did you do \[\huge \frac{1000 - 4(3.14)(3.5)(3.5)}{2(3.14)(3.5)}?\]

Answer 21

Calculator FTW!

Answer 22

yup i did that. and i am using a calculator. why are you being such an a** ? @ParthKohli & maybe i like writing in caps. doesnt seem to bother anyone else !!!

Answer 23

Who's being an a**, ma'am?

Answer 24

you.

Answer 25

orly?

Answer 26

try multiplying 4 x 3.14 x 3.5 x 3.5 first what do you get?

Answer 27

@lgbasallote : 153.86

Answer 28

153.86... try dividing that by 2 x 3.14 x 3.5

Answer 29

FTW = For the win, not what you think.

Answer 30

38.49

Answer 31

@rajathsbhat : not one of my options

Answer 32

Numerator is : \[1000 - 4(22)(3.5)(3.5)/7\]

1000 - 4(22)(0.5)(3.5) = 1000 - 154 = 846...

And the Denominator is :\[2(22)(3.5)/7 = 2(22)(0.5)\] = 22..

Now h = 846/22 = 38.45... I am getting 38.45 as answer guys...

Answer 33

im getting something aroung 38.4-38.5 too

Answer 34

around*

Answer 35

close to 41.97.

Answer 36

*close enough*

Answer 37

hah lol..i like your thinking ;)

Answer 38

It is not close to 41.97..
There is something wrong in the question or options given...

Answer 39

i have to show my work and your not proving how you get it. . 38.5 is nothing close to 41.97 & @waterineyes : thank you

Answer 40

Welcome dear...

Answer 41

lol isnt the formula i wrote proof enough why we're getting 38.5 =))

Answer 42

great point, lgba.

Answer 43

I think our formula is wrong...

Answer 44

no way. Now you're just being silly.

Answer 45

i tried lateral surface area too no cheese :/

Answer 46

@Senior012 what is the unit of measurement for the choices? maybe that can explain the answers...

Answer 47

What's the point of fighting guys?

Answer 48

Sorry the formula is :

\[h = (SA - 2\pi r^2)/2\pi r\]The Numerator is :

1000−4(22)(3.5)(3.5)/7

= 1000 - 4(22)(0.5)(3.5) = 1000 - 77 = 923...

And the Denominator is :

2(22)(3.5)/7=2(22)(0.5)

= 22..

Now h = 923/22 = 41.95...

Now the answer is pretty close to 41.97..
Isn't it....????

Answer 49

oops oh yeah 2pi r^2

Answer 50

i must have thought that the area of a circle is 2 pi r^2 for an odd reason

Answer 51

Ha ha ha...Sometimes it happens...

Answer 52

all hail the great @waterineyes for figuring it out---seriously.

Answer 53

Discussion always solves the problem...