About NP complete problems, we learned that if a polynomial algorithm could be found for one NP complete problem, then that algorithm could be used to solve any problem in NP in polynomial time. My question is, can polynomial time approximation algorithms (like the ones we learned in this module) can be used in a similar way? That is, if we have one polynomial time approximation algorithm, can we use that algorithm as a subroutine to approximately solve other NP problems in polynomial time?