To find the missing value \( f(4) \) using the function \( f(x) = 3(1.2)^x \), we can substitute \( x = 4 \) into the equation.
\[ f(4) = 3(1.2)^4 \]
First, we need to calculate \( (1.2)^4 \):
\[ (1.2)^4 = 1.2 \times 1.2 \times 1.2 \times 1.2 \]
Calculating it step by step:
\[ 1.2 \times 1.2 = 1.44 \]
Next, multiply \( 1.44 \) by \( 1.2 \):
\[ 1.44 \times 1.2 = 1.728 \]
Then, multiply \( 1.728 \) by \( 1.2 \):
\[ 1.728 \times 1.2 = 2.0736 \]
Now we multiply this by 3:
\[ f(4) = 3 \times 2.0736 = 6.2208 \]
Rounding to two decimal places, we have:
\[ f(4) \approx 6.22 \]
Thus, the missing value \( f(4) \) is:
\[ \boxed{6.22} \]