# What is the Least Common Multiple of 55 and 72?

*Least common multiple* or lowest common denominator (lcd) can be calculated in two way; with the LCM formula calculation of greatest common factor (GCF), or multiplying the prime factors with the highest exponent factor.

Least common multiple (LCM) of 55 and 72 is **3960**.

LCM(55,72) = 3960

## Least Common Multiple of 55 and 72 with GCF Formula

The formula of **LCM** is LCM(a,b) = ( a × b) / GCF(a,b).

We need to calculate greatest common factor 55 and 72, than apply into the LCM equation.

GCF(55,72) = 1

LCM(55,72) = ( 55 × 72) / 1

LCM(55,72) = 3960 / 1

LCM(55,72) = 3960

## Least Common Multiple (LCM) of 55 and 72 with Primes

Least common multiple can be found by multiplying the highest exponent prime factors of 55 and 72. First we will calculate the **prime factors of 55 and 72**.

### Prime Factorization of 55

Prime factors of 55 are 5, 11. Prime factorization of **55** in exponential form is:

55 = 5^{1} × 11^{1}

### Prime Factorization of 72

Prime factors of 72 are 2, 3. Prime factorization of **72** in exponential form is:

72 = 2^{3} × 3^{2}

Now multiplying the highest exponent prime factors to calculate the **LCM of 55 and 72**.

LCM(55,72) = 5^{1} × 11^{1} × 2^{3} × 3^{2}

LCM(55,72) = 3960