Finding the Fourth Proportional to 5,139.56, 7,712.22 and 2,831.72

Step by Step Solution

1. Step 1: Write the proportion equation
   5,139.56 : 7,712.22 = 2,831.72 : x
2. Step 2: Convert to fraction form
   5,139.56/7,712.22 = 2,831.72/x
3. Step 3: Cross multiply
   5,139.56x = 7,712.22 × 2,831.72
4. Step 4: Simplify right side
   5,139.56x = 21,838,847.62
5. Step 5: Solve for x
   x = 21,838,847.62/5,139.56
6. Step 6: Final answer
   x = 4,249.17