Finding the Fourth Proportional to 3,906.72, 5,391.27 and 2,138.31

Step by Step Solution

1. Step 1: Write the proportion equation
   3,906.72 : 5,391.27 = 2,138.31 : x
2. Step 2: Convert to fraction form
   3,906.72/5,391.27 = 2,138.31/x
3. Step 3: Cross multiply
   3,906.72x = 5,391.27 × 2,138.31
4. Step 4: Simplify right side
   3,906.72x = 11,528,206.55
5. Step 5: Solve for x
   x = 11,528,206.55/3,906.72
6. Step 6: Final answer
   x = 2,950.87