Chapter 5 - Number Theory and the Real Number System - 5.1 Number Theory: Prime and Composite Numbers - Exercise Set 5.1 - Page 256: 63

The least common multiple of the two numbers is $360$.

Factor each number to obtain: $72=9(8)=3(3)(2)(2)(2)=3(3)(2)(2)(2) \\120=3(40)=3(5)(8)=3(5)(2)(2)(2)=5(3)(2)(2)(2)$ Thus, the least common multiple of the two numbers is $5(3)(3)(2)(2)(2)=360$.