# calculus

posted by
**John**
.

A hole of a radius of 1cm is pierced in a sphere of a 4cm radius. Calculate the volume of the remaining sphere.

I know that the volume of a sphere with an exterior radius is of:

V = pie(R^2 - r^2) dH

where R^2 is the exterior surface area and r^2 is the interior surface area. dH is the thickness.

How would I go about finding the thickness? And for R and r, do I simply just plug in the values that are given to me?

Thank you.