How to Find GCF of 91/66, 78/90, 21/31?

GCF of 91/66, 78/90, 21/31

Created By : Veerendra
Reviewed By : Phani Ponnapalli
Last Updated at : Mar 29,2023

Use our free GCF of Fractions Calculator tool to compute the GCF of 91/66, 78/90, 21/31 i.e 1/30690 easily. The following is the detailed procedure to determine the greatest common factor of fractions 91/66, 78/90, 21/31.

Enter two or more fractions separated by "commas"

Ex: 2/3, 5/7 or 3/5, 5/9, 7/3

What is the GCF of 91/66,78/90,21/31?

Given fractions are 91/66,78/90,21/31

To find the GCF of fractions, we have to find the GCF of numerator numbers and LCM of denominator numbers. Its formula is given by

GCF of Fraction = Greatest Common Factor of Numerator/Least Common Multiple of Denominators

In the fractions 91/66,78/90,21/31, numerators are 91,78,21

Denominators are 66,90,31

The GCF of 91,78,21 is 1 .

LCM of 66,90,31 is 30690.

The greatest common factor of 91/66,78/90,21/31 = [GCF of 91,78,21]/[LCM of 66,90,31]= 1/30690

Therefore, the GCF of 91/66,78/90,21/31 is 1/30690.

Greatest Common Factor of 91,78,21

To find the highest common factor of 91,78,21, we have to find the factors of both numbers and list the highest common factor.

The factors of 91 are 1, 7, 13, 91

The factors of 78 are 1, 2, 3, 6, 13, 26, 39, 78

The factors of 21 are 1, 3, 7, 21

The HCF of 91,78,21 is 1.

Lets's calculate GCF of 91,78,21

Greatest Common Factor (GCF) of 91,78,21 By Common Division

∴ So GCF of numbers is 1 because of no common factors present between them.

Greatest Common Factor of 91,78,21 By Matching Biggest Common Factor Method

Now, list down the factors of 91

1,7,13,91

Now, list down the factors of 78

1,2,3,6,13,26,39,78

Now, list down the factors of 21

1,3,7,21

Greatest Common Factor

We found the factors 91,78,21 . The biggest common factor number is the GCF number.
So the greatest common factor 91,78,21 is 1.

Lets's calculate LCM of 66,90,31

Lowest Common Multiple of 66,90,31 using Common Division

2	66, 90, 31
3	33, 45, 31
	11, 15, 31

∴ So the LCM of the given numbers is 2 x 3 x 11 x 15 x 31 = 30690

Thus GCF of Fractions = GCF of Numerators/LCM of Denominators = 1/30690

Therefore, the GCF of Fractions 91/66,78/90,21/31 is 1/30690

Least Common Multiple of 66,90,31 with GCF Formula

The formula of LCM is LCM(a₁,a₂,a₃....,a_n) = ( a₁ × a₂ × a₃ × .... × a_n) / GCF(a₁,a₂,a₃....,a_n) x common factors(if more than 2 numbers have common factors).

We need to calculate greatest common factor of 66,90,31 and common factors if more than two numbers have common factor, than apply into the LCM equation.

GCF(66,90,31) = 1

common factors(in case of two or more numbers have common factors) = 6

GCF(66,90,31) x common factors =1 x 6 = 6

LCM(66,90,31) = ( 66 × 90 × 31 ) / 6

LCM(66,90,31) = 184140 / 6

LCM(66,90,31) = 30690

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FAQs on GCF of Fractions of 91/66, 78/90, 21/31

1. What is the HCF of 91,78,21?

The HCF of 91,78,21 is 1

2. What is the GCF of a fraction?

The GCF of a fraction is defined as the greatest fraction that divides exactly into 2 or more fractions.

3. How to find GCF in Fractions?

Answer: GCF of fractions can be found using the simple formula GCF of Fractions = GCF of Numerators/LCM of Denominators.

4. What is the GCF of Fractions for 91/66, 78/90, 21/31?

Answer: GCF of Numerators as per given numbers 91/66, 78/90, 21/31 is

GCF of Numerators i.e. for 91,78,21 is 1

LCM of denominators i.e. for 66,90,31 is 30690.

Thus, GCF of Fractions is 1/30690.Finally, GCF of Fractions for 91/66, 78/90, 21/31 is 1/30690.