LCM( 120, 360 ) = 360
The formula for finding LCM is
$$ \text{LCM} (a, b) = \frac{ a \cdot b }{ \text{GCD}(a,b)} $$In this example we have: a = 120, b = 360 and GCD(120, 360) = 120.
$$ \text{LCM} (120, 360) = \frac{ 120 \cdot 360 }{ \text{GCD}(120,360)} = \frac{ 43200 }{ 120 } = 360 $$