Finding the Fourth Proportional to 139,920.90, 193,097.67 and 78,686.36

Step by Step Solution

1. Step 1: Write the proportion equation
   139,920.90 : 193,097.67 = 78,686.36 : x
2. Step 2: Convert to fraction form
   139,920.90/193,097.67 = 78,686.36/x
3. Step 3: Cross multiply
   139,920.90x = 193,097.67 × 78,686.36
4. Step 4: Simplify right side
   139,920.90x = 15,194,152,776.78
5. Step 5: Solve for x
   x = 15,194,152,776.78/139,920.90
6. Step 6: Final answer
   x = 108,591.02