1. The problem statement, all variables and given/known data A cylindrical drill with radius r1 is used to bore a hole throught the center of a sphere of radius r2. Find the volume of the ring shaped solid that remains. 2. Relevant equations x=r*cos(theta) y=r*sin(theta) 3. The attempt at a solution i know that the boundaries are: for theta: 0 to 2*pi for r: r1 to r2 i just dont know the equation to use in the double integral.. the equation of the cylinder is x^2+y^2= r1^2 i know that much.