The "Pi in the Sky" math challenge gives students a chance to find solutions to real-world problems all while using math and pi just like NASA scientists and engineers. In this problem from the seventh installment of the set, students use the mathematical constant pi to measure the water depth of an area mapped by the CORAL mission. Materials Pi in the Sky 7: Coral Calculus – Download PDF Pi in the Sky 7: Coral Calculus answer key – Download PDF (also available as a text-only doc ) Background F