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 11th set, students use pi to calculate the position of Earth in its orbit as a signal is sent from a spacecraft in deep space. Materials Pi in the Sky 11: Receiver Riddle worksheet – download PDF (for best results, download and print from Adobe Reader) Pi in the Sky 11: Receiver