1. The volume of a cylinder is 2400cm^3 and the height is 6cm. Find the radius of the cylinder to the nearest tenth by first isolating r, and then by substituting known values.

2. Expand and simplify the expression π(R+r)(R-r) to explain why it represents the area of a ring. Draw a diagram of the ring and identify R and r.

and can somebody give me a website to learn how to solve these types of problems it would be much appreciated.