First, calculate \(\Sigma(x - 45)\):

\(\Sigma(x - 45) = \Sigma x - 20 \times 45 = 1218 - 20 \times 45 = 318\)

Next, use the variance formula to find \(\Sigma(x - 45)^2\):

The variance formula is \(\frac{\Sigma(x - 45)^2}{20} - \left(\frac{\Sigma(x - 45)}{20}\right)^2 = 4.2^2\)

Substitute \(\Sigma(x - 45) = 318\):

\(\frac{\Sigma(x - 45)^2}{20} - \left(\frac{318}{20}\right)^2 = 4.2^2\)

Calculate \(4.2^2 = 17.64\) and \(\left(\frac{318}{20}\right)^2 = 252.81\):

\(\frac{\Sigma(x - 45)^2}{20} = 17.64 + 252.81 = 270.45\)

\(\Sigma(x - 45)^2 = 270.45 \times 20 = 5409\)