Erg! I need some help!!!

[birdie_boo]

So, I have this ONE math problem that is killing me! Two cylinders have diameters of 16 and 21. What is the difference in their circumferences? Use 3 for pi. Thats the whole problem! So if anyone could possibly help me with that before Monday, that would be perfect!

 

[gortwell]

circumference = \(\displaystyle \pi\ \ \)* diameter, or in your particular instance 3 x diameter