Finding the Fourth Proportional to 538,499.33, 807,686.11 and 139,108.78

Step by Step Solution

1. Step 1: Write the proportion equation
   538,499.33 : 807,686.11 = 139,108.78 : x
2. Step 2: Convert to fraction form
   538,499.33/807,686.11 = 139,108.78/x
3. Step 3: Cross multiply
   538,499.33x = 807,686.11 × 139,108.78
4. Step 4: Simplify right side
   538,499.33x = 112,356,229,385.05
5. Step 5: Solve for x
   x = 112,356,229,385.05/538,499.33
6. Step 6: Final answer
   x = 208,646.93