What is the HCF of 55 and 77 and 132?

The Highest Common Factor (HCF) of 55, 77, and 132 is the largest number that divides all three numbers without leaving a remainder. To find the HCF, you can first find the prime factors of each number: 55 = 5 x 11, 77 = 7 x 11, and 132 = 2^2 x 3 x 11. Then, identify the common prime factors among the numbers, which are 11. Therefore, the HCF of 55, 77, and 132 is 11.