450
Step-by-step explanation:
Find the prime factorization of the two numbers (using a factor tree)
90 = 2 * 3 * 3 * 5
150 = 2 * 3 * 5 * 5
(The common factors are bolded)
To find LCM, multiply all the factors from the two prime factorizations
However, only multiply the common ones once
2 * 3 * 3 * 5 * 5 = 450