ChallengeChallengeCircles & Lines ShareCircles & Lines · Challenge problemHow many ordered pairs of positive integers (a,b)(a, b)(a,b) satisfy lcm(a,b)=72\operatorname{lcm}(a, b) = 72lcm(a,b)=72 and gcd(a,b)=6\gcd(a, b) = 6gcd(a,b)=6?A222B444C666D888E121212Check Show answer Walk through it step by step Practice more like this Review this concept