Finding the Fourth Proportional to 139,133.12, 192,003.68 and 78,702.40

Step by Step Solution

1. Step 1: Write the proportion equation
   139,133.12 : 192,003.68 = 78,702.40 : x
2. Step 2: Convert to fraction form
   139,133.12/192,003.68 = 78,702.40/x
3. Step 3: Cross multiply
   139,133.12x = 192,003.68 × 78,702.40
4. Step 4: Simplify right side
   139,133.12x = 15,111,150,424.83
5. Step 5: Solve for x
   x = 15,111,150,424.83/139,133.12
6. Step 6: Final answer
   x = 108,609.30