## ameryn.love17 3 years ago Find the surface area of a cylinder with a base diameter of 8ft and a height of 9ft . Write your answer in terms of , and be sure to include the correct unit.

1. ameryn.love17

|dw:1330128011662:dw|

2. jryaaaan18

find the area of the circle forming the top of the cylinder, then multiply it by your height to give you the volume

3. bahrom7893

pi*16*9

4. bahrom7893

144pi(ft^3)

5. virtu

The best way to visualize this problem is by taking a piece of paper and rolling it up to look like a cylinder. You will have a hollow cylinder, but we can fix that in the problem. We have two circles and one rectangle This will give us the surface area. First we will compute the area of a single circle the area of a circle is defined as pi*r^2=a the diameter (d) of a circle is 2*radius (r) d=2r therefore d/2=r d=8 8/2=4=r pi*4^2=area of a single circle but we have two circles (one on top and one on bottom) 2(pi*4^2)=area of two circles We now need to find the area of the edges. This is where the paper will come in to handy. Take a sheet of paper and roll it up in a circle. You'll notice that you now have a cylinder. The area of the paper = length*width. Our given length is 9 we need to find our width. In order to do that we have to find a relationship between the square and the circles. The length of the circle's edge is the width that we are looking for. So we need to find the circumeference. the circumference of a circle (our width) is = 2*pi*r 2*pi*4=width width*height = area of sides of cylinder=area of a square rolled up area1 = 2(pi*4^2)=100.53 area 2 = (2*pi*4)*9 = 226.1946710584651 area1+area2= 326.7256359733385ft^2

6. ameryn.love17

whoa!!!

7. ameryn.love17

lol not to sound stupid but wheres the answer

8. virtu

bottom

9. saifoo.khan

That

10. saifoo.khan

is

11. saifoo.khan

HUGE.

12. ameryn.love17

it is

13. virtu

Does it help?

14. ameryn.love17

im trying it out

15. Chlorophyll

SA = 2 pi r^2 + 2 pi r h = 2 pi r ( r + h) = 2 pi 4 ( 4 + 9) = 326.6 ft^2

16. Chlorophyll

Any comment, ameryn?

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