Finding the Fourth Proportional to 139,113.78, 191,986.56 and 78,684.48

Step by Step Solution

1. Step 1: Write the proportion equation
   139,113.78 : 191,986.56 = 78,684.48 : x
2. Step 2: Convert to fraction form
   139,113.78/191,986.56 = 78,684.48/x
3. Step 3: Cross multiply
   139,113.78x = 191,986.56 × 78,684.48
4. Step 4: Simplify right side
   139,113.78x = 15,106,362,640.59
5. Step 5: Solve for x
   x = 15,106,362,640.59/139,113.78
6. Step 6: Final answer
   x = 108,589.98