1. The problem states that two parallel lines $m$ and $n$ are intersected by a transversal $p$. The angle between $p$ and $m$ is $43^\circ$, and we need to find the value of the angle $x^\circ$ formed between $p$ and $n$ which is vertically opposite to the $43^\circ$ angle. 2. When two parallel lines are cut by a transversal, corresponding angles are equal. Also, vertically opposite angles are equal. 3. Since $x^\circ$ is vertically opposite to the $43^\circ$ angle, by the property of vertically opposite angles: $$x = 43$$ 4. Therefore, the value of $x$ is $43^\circ$. Final answer: $x = 43^\circ$