LCM( 16, 28 ) = 112
The formula for finding LCM is
$$ \text{LCM} (a, b) = \frac{ a \cdot b }{ \text{GCD}(a,b)} $$In this example we have: a = 16, b = 28 and GCD(16, 28) = 4.
$$ \text{LCM} (16, 28) = \frac{ 16 \cdot 28 }{ \text{GCD}(16,28)} = \frac{ 448 }{ 4 } = 112 $$