## anonymous 5 years ago Solve for the variable given the surface area S of the right cylinder.

1. anonymous

2. anonymous

Alright, you know the general formulas of the cylinder's Surface Area :$SA = 2\pi r^2 + 2\pi r h$ now notice that x in the drawing represents h :) so you can re-write the equation and you'll get : $SA = 2\pi r^2 + 2\pi r x$ Now we ask ourselves, what do we have given? Given: - SA = 452.4in^2 - R = 4 in Required to find x , so substitute the given in the equation and solve for x :) Give it a try ^_^

3. anonymous

$2\times3.14\times4^{2}+2\times3.14\times4timesx$

4. anonymous

100.48+25.12x

5. anonymous

x=75.36in

6. anonymous

I didn't calculate it , but since you followed the steps, then I guess you're right :)

7. anonymous

8. anonymous

don't forget you have the surface area :) (452.4 - 2pi(4)^2 )/ 4pi=x x = 28.00, my bad lol

9. anonymous

no wait, you divide by 8pi >_< so you'll get : x = 14.00 LOL, I'm sure now

10. anonymous

$(452.4 - (12)(2)\pi )/2\pi(4) = x$ $x = (351.87)/8\pi$ $x = 14 inches$ sorry about the mess :)

11. anonymous

12. anonymous

so x= 14in?

13. anonymous

yes lol, I apologize for the mess ^_^

14. anonymous

okay thank you

15. anonymous

np ^_^