The "Pi in the Sky" math challenge gives students a chance to take part in recent discoveries and upcoming celestial events, all while using math and pi just like NASA scientists and engineers. In this problem from the ninth set, students use the mathematical constant pi to calculate the volume and density of Mars' liquid core. Materials Pi in the Sky 9: Core Conundrum worksheet – download PDF Pi in the Sky 9: Core Conundrum answer key – download PDF (also available as a text-only doc) Backgrou