Answer
Final compound formed has the formula $CH_{3}COOK$.
Work Step by Step
The metal cation is $K^{+}$
The polyatomic anion is $CH_{3}COO^{-}$
Combine 1 $K^{+}$ and 1 $CH_{3}COO^{2-}$ to balance the charge.
Final compound formed has the formula $CH_{3}COOK$.