For the numbers to be in arithmetic progression, the difference between consecutive terms must be constant.
Thus, the difference between the second and first terms should equal the difference between the third and second terms:
\[
(4K - 6) - (K + 2) = (3K - 2) - (4K - 6).
\]
Simplifying both sides:
\[
3K - 8 = -K + (4)
\]
Solving for \( K \):
\[
3K + K = 4 + 8 \quad \Rightarrow \quad 4K = 12 \quad \Rightarrow \quad K = (3)
\]