Finding the Fourth Proportional to 408,793.59, 613,216.31 and 128,321.91

Step by Step Solution

1. Step 1: Write the proportion equation
   408,793.59 : 613,216.31 = 128,321.91 : x
2. Step 2: Convert to fraction form
   408,793.59/613,216.31 = 128,321.91/x
3. Step 3: Cross multiply
   408,793.59x = 613,216.31 × 128,321.91
4. Step 4: Simplify right side
   408,793.59x = 78,689,087,500.74
5. Step 5: Solve for x
   x = 78,689,087,500.74/408,793.59
6. Step 6: Final answer
   x = 192,491.00