What are all the common factors of 15, 45, and 90

Solution:

The common factors of 15, 45, and 90 can be found out by first finding out the individual factors of the number and then subsequently identifying the common factors.

Hence the factors of 15 are:

1, 3 and 5

The factors of 45 are:

1, 3, 5, 9, 15

The factors of 90 are:

1, 2, 3, 5, 6, 9, 15, 18, 30, 45

The common factors therefore of 15, 45, and 90 are 1, 3, 5

An alternative method is to identify the prime factors of the three numbers first:

15 = 3 × 5

45 = 3 × 3 × 5

90 = 3 × 3 × 2 × 5 = 2 × 3 × 3 × 5

From above the common factors are 3 and 5. Besides the two the other common factor is 1

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What are all the common factors of 15, 45, and 90

Summary:

All the common factors of 15, 45, and 90 are 1, 3 and 5