Question

what is the surface area of a cylinder that is r=9cm,h=15cm round to tenth of a square unit

Answer 1

Well, let us start with what counts as surface area. Can you explain?

Answer 2

no i cant the book just give me r=9cm,h=15cm

Answer 3

Forget dimensions. Start with cylinder shape. What would be part of its "surface"?

Answer 4

is it 2(pir2)+(2pir)

Answer 5

Well....you are missing the length of the cylinder.

Answer 6

If you get the concept of the surface of a cylinder as the are of two circles on top and bottom, plus the length of the circumference of the circle across the cylinder, then you will be right. Then, it is a matter of figuring out the "formulas" and plugging values of the respective dimensions.

Answer 7

i got 254.469 as my answer

Answer 8

i think i did something wrong

Answer 9

2*pi*9^2 + 2*pi*9*15

Answer 10

The area of the top which is a circle is pir^2 So the top and bottom area is the total of the two circles or 2pir^2. The radius is 9 so that makes a total of 162pi. Now how about the rest of the cylinder. We have eliminated the top and bottom of the "can" so not we have a tube left. If we split the "tube" open, we will have a rectangle. The height of the rectangle is the height of the cylinder and the base of the rectangle is the circumference of the circle. so the area of the rectangle is 2pir(h) Add that to the 162pi and you will have the total area or 432 pi

Answer 11

thank you now im able to complete my others problems like this

Answer 12

AWESOME!!! YOU ARE GREAT!

Answer 13

thanks you