Finding the Fourth Proportional to 139,978.73, 209,843.76 and 54,569.90

Step by Step Solution

1. Step 1: Write the proportion equation
   139,978.73 : 209,843.76 = 54,569.90 : x
2. Step 2: Convert to fraction form
   139,978.73/209,843.76 = 54,569.90/x
3. Step 3: Cross multiply
   139,978.73x = 209,843.76 × 54,569.90
4. Step 4: Simplify right side
   139,978.73x = 11,451,153,728.07
5. Step 5: Solve for x
   x = 11,451,153,728.07/139,978.73
6. Step 6: Final answer
   x = 81,806.38