What is the greatest common factor of 18 54 90?
To find the greatest common factor (GCF) of 18, 54, and 90, we first need to find the prime factorization of each number. The prime factorization of 18 is 2 * 3^2, the prime factorization of 54 is 2 * 3^3, and the prime factorization of 90 is 2 * 3^2 * 5. To find the GCF, we identify the common prime factors among the numbers, which are 2 and 3^2. Therefore, the GCF of 18, 54, and 90 is 2 * 3^2, which equals 18.