1. **Stating the problem:** We have a quadrilateral R S T U with diagonal S U. Given angles are \(\angle R = 30^\circ\) and \(\angle R S U = 25^\circ\). The segment \(R U = 4b - 1\) and \(S T = 23\). Point B lies on diagonal S U. We need to analyze or find relationships involving these elements. 2. **Understanding the geometry:** Since \(\angle R S U = 25^\circ\) is an angle at vertex S between points R and U, and \(\angle R = 30^\circ\) is at vertex R, these angles help define the shape and possibly relate sides. 3. **Using the given lengths:** \(R U = 4b - 1\) is an expression involving variable \(b\), and \(S T = 23\) is a fixed length. 4. **Next steps:** Without additional information such as side lengths or other angles, we cannot solve for \(b\) or other unknowns directly. More data or a specific question is needed to proceed. **Summary:** The problem provides angles and some side lengths in a quadrilateral with a diagonal and a point on it, but lacks sufficient information to solve for \(b\) or other unknowns. Please provide a specific question or additional data.