Black Hole Calculations

The Schwarschild radius (e.g. the radius of the event horizon; Rs) is directly proportional to the mass of a black hole. If a 1 solar mass black hole is has a schwarschild radius R_s=3 kilometers, what is a schwarschild radius of a 1 earth mass black hole? (Mass of Sun = 2 x 10³⁰ kg; Mass of Earth = 6 x 10²⁴ kg)

1. What is a Schwarschild radius of a 100 million solar mass black hole?

2. Now, calculate the density of each black hole. The density is Mass/Volume where Volume = R_S³ (yes this is an approximation).

3. Compare the density of each by taking the ratio. Which is denser? Is this surprising to you?