A metal pipe has outer diameter 5mm and 3mm thick metal. Calculate the volume used to make this metal pipe if the length of the pipe is 18cm long.

Expert Answers
durbanville eNotes educator| Certified Educator

To calculate, basically find the outer volume minus the inner volume:

`V=pir^2h`  becomes `V=pi h ((r_(1))^2- (r_(2))^2)`

First convert the cm into mm. Thus the length = 180mm.The thickness of the pipe is 3mm so the inner diameter (d) = 2mm 

If `d_1 = 5 therefore r_1=2.5`  and `d_2=2therefore r_2=1`

`V=pi times 180( 2.5^2-1^2)`

`therefore V=2968.81 mm^3`