Analyse the below picture and fill in the following blanks:
1. Vertex \(Q\) is opposite to the side .
2. Side \(PR\) is opposite to the vertex .
3. Median \(RU\) is a line segment that connects the vertex \(R\) to the midpoint of the opposite side .
4. By the definition of median, it can be concluded that the side \(PR\) is twice as that of .