What is the LCM of 45 and 54 and 72?

To find the least common multiple (LCM) of 45, 54, and 72, we first need to find the prime factorization of each number. The prime factorization of 45 is 3^2 * 5, 54 is 2 * 3^3, and 72 is 2^3 * 3^2. Then, we take the highest power of each prime factor that appears in any of the numbers: 2^3 * 3^3 * 5 = 540. Therefore, the LCM of 45, 54, and 72 is 540.