The average of square of first 6 consecutive even numbers is:

The first 6 consecutive even numbers are:

$2, 4, 6, 8, 10, 12$

Their squares are:

$4, 16, 36, 64, 100, 144$

Sum of squares:

$4 + 16 + 36 + 64 + 100 + 144 = 364$

Average:

$\frac{364}{6} = 60.666\dots \approx 60.66$