Approximation rhymes with:
consummation, summation, acclamation, acclimation, amalgamation, animation, automation, consummation, defamation, estimation, exclamation, inflammation, intimation, proclamation, reclamation, summation
consummation, summation, acclamation, acclimation, amalgamation, animation, automation, consummation, defamation, estimation, exclamation, inflammation, intimation, proclamation, reclamation, summation