C++ Q.139.How does a polymorphism play constructive role in application development? Which type of polymorphism is essential for the computation of distance among two cities from the specific...

C++ Q.139.How does a polymorphism play constructive role in application development? Which type of polymorphism is essential for the computation of distance among two cities from the specific location. The unit of measurements are feet and inch. (Also use standard unit if essential).