To find the 7th value in the arithmetic sequence described by the explicit formula \( A_n = 2.5 + (n - 1) \cdot 4 \), we need to substitute \( n = 7 \) into the formula.
\[ A_7 = 2.5 + (7 - 1) \cdot 4 \] \[ A_7 = 2.5 + (6) \cdot 4 \] \[ A_7 = 2.5 + 24 \] \[ A_7 = 26.5 \]
Therefore, the 7th value in the sequence is \( A_7 = 26.5 \).