The given sequence appears to follow a pattern, and it looks like an arithmetic sequence. The terms given are:

• $a_1 = 75$
• $a_2 = 91.5$
• $a_3 = 111.63$

To verify if this is an arithmetic sequence, we need to check if the difference between consecutive terms is constant:

1. Difference between $a_2$ and $a_1$: $d = 91.5 - 75 = 16.5$

2. Difference between $a_3$ and $a_2$: $d = 111.63 - 91.5 = 20.13$

Since the differences are not the same, this isn't an arithmetic sequence. This suggests that the sequence may follow a different rule.

It is possible that the sequence follows some other pattern, but to find the sum of the first 8 terms, I'll need more information on how the sequence progresses beyond the third term.

Could you provide more terms or specify the type of sequence?