Finding the Fourth Proportional to 368,705.31, 553,059.71 and 128,818.20

Step by Step Solution

1. Step 1: Write the proportion equation
   368,705.31 : 553,059.71 = 128,818.20 : x
2. Step 2: Convert to fraction form
   368,705.31/553,059.71 = 128,818.20/x
3. Step 3: Cross multiply
   368,705.31x = 553,059.71 × 128,818.20
4. Step 4: Simplify right side
   368,705.31x = 71,244,156,334.72
5. Step 5: Solve for x
   x = 71,244,156,334.72/368,705.31
6. Step 6: Final answer
   x = 193,227.91