Given the numbers:
30, 90, and 210
To find the Greatest Common Factors of the numbers, find the factors of each number,
Factors of 30 = 1, 2, 3, 5, 6, 10, 15, 30
Factors of 90 = 1, 2, 3, 5, 6, 9, 10, 15, 18, 30, 45, 90
Factors of 210 = 1, 2, 3, 5, 6, 7, 10, 14, 15, 21, 30, 35, 42, 70, 105, 210
The common factors of the three numbers are: The common factors are factors which can be found in the factors of all three numbers above.
They are:
1, 2, 3, 5, 6, 10, 15, and 30
From the numbers above, the Greatest Common Factor is 30
ANSWER:
30
Method 2:
To use the method of prime factors to find The GCF.
First find the prime factors of each number.
Prime factor of 30 = 2 x 3 x 5
Prime factors of 90 = 2 x 3 x 3 x 5
Prime factors of 210 = 2 x 3 x 5
Now the common prime factors are:
2, 3, and 5.
Now multiply the common prime factors to find the GCF:
Therefore, the GCF of 30, 90, and 210 is 30
ANSWER:
30