Finding the Fourth Proportional to 139,339.30, 192,288.61 and 81,980.78

Step by Step Solution

1. Step 1: Write the proportion equation
   139,339.30 : 192,288.61 = 81,980.78 : x
2. Step 2: Convert to fraction form
   139,339.30/192,288.61 = 81,980.78/x
3. Step 3: Cross multiply
   139,339.30x = 192,288.61 × 81,980.78
4. Step 4: Simplify right side
   139,339.30x = 15,763,970,508.69
5. Step 5: Solve for x
   x = 15,763,970,508.69/139,339.30
6. Step 6: Final answer
   x = 113,133.70