Finding the Fourth Proportional to 408,930.21, 613,419.83 and 128,447.46

Step by Step Solution

1. Step 1: Write the proportion equation
   408,930.21 : 613,419.83 = 128,447.46 : x
2. Step 2: Convert to fraction form
   408,930.21/613,419.83 = 128,447.46/x
3. Step 3: Cross multiply
   408,930.21x = 613,419.83 × 128,447.46
4. Step 4: Simplify right side
   408,930.21x = 78,792,218,434.89
5. Step 5: Solve for x
   x = 78,792,218,434.89/408,930.21
6. Step 6: Final answer
   x = 192,678.89