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 many times the Mars rover Opportunity's wheels rotated to get the rover to a marathon distance. Materials Pi in the Sky 2: Mars Marathon worksheet – download PDF Pi in the Sky 2 answer key (first problem) – download