Math: Geometry
posted by Marcus .
The circumference of the base of a cylinder is 16 cm. The height of the cylinder is 10cm.
a. What is the surface area of the cylinder?
b. What is the volume of the cylinder?
Need help on this one. I have the formula but I'm a little confused because I don't know what the radius is. I think that if I have that then I will be able to just plug in the other numbers.

The circumference is equal to (2)(pi)(r).
Since you know the circumference is 16,and you know the value of pi and 2,solve for r. 
Circumference = PI * d
Solve for d and divide by 2.
For more information, check this site.
http://www.mathgoodies.com/lessons/vol2/circumference.html