Finding the Fourth Proportional to 428,957.27, 643,419.72 and 129,429.86

Step by Step Solution

1. Step 1: Write the proportion equation
   428,957.27 : 643,419.72 = 129,429.86 : x
2. Step 2: Convert to fraction form
   428,957.27/643,419.72 = 129,429.86/x
3. Step 3: Cross multiply
   428,957.27x = 643,419.72 × 129,429.86
4. Step 4: Simplify right side
   428,957.27x = 83,277,721,063.74
5. Step 5: Solve for x
   x = 83,277,721,063.74/428,957.27
6. Step 6: Final answer
   x = 194,139.90