The z-score = (the observed value - the mean) / standard deviation.
In our problem,
the observed value = 52 points
the mean = 24.8 points
the standard deviation = 8.5 points
Let's plug our numbers into the formula above.
Z-score = (52 points - 24.8 points) / 8.5 points = 3.2
This means that at the homecoming game the team scored 3.2 times the standard deviation of the average points.