\[56,\ 64,\ \ldots,\ 176.\]
\[d = 64 - 56 = 8,\ \ a_{n} = 176\]
\[56 + 8 \cdot (n - 1) = 176\]
\[56 + 8n - 8 = 176\]
\[8n = 128\]
\[n = 16.\]
\[S = \frac{56 + 176}{2} \cdot 16 = 232 \cdot 8 = 1856.\]
\[Ответ:\ \ 1856.\]