Let be the outside radius, inside radius, and thickness respectively.
Thickness is by:
The volume is given by (volume of outside minus inside):
.
See what you did wrong?
The volume of a metallic cylindrical pipe is 748 cu.cm. Its length is 14 cm & its external radius is 9 cm. How do I find its thickness?
This is what I tried:
pi x r x r x h = 748
pi x r x r x 14 = 748
r x r = 17
r = 4.17 (this is the internal radius)
Now thickness = external radius - internal radius
thickness = 9 - 4.17 = 5.83 cm
But the answer is wrong. Can someone help me out with this?
Thanks,
Ron
Well, this is your problem. Are you told specifically that the "volume" given refers to the inner capacity of the pipe? the interpretation of snowtea and Soroban, that the volume is the volume of material making up the pipe seems more reasonable to me- especially since by your interpretation, the outer radius is irrelevant. If we call the inner radius "r" then the inner volume of the pipe is just . From that, so that inches.