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 set , students use the mathematical constant pi to calculate how long it takes for the Mars Reconnaissance Orbiter to circle the Red Planet. Materials Pi in the Sky 3: Round Recon worksheet – download PDF Pi in the Sky 3 answer key (second problem) – download PDF Background NASA'