Finding the Fourth Proportional to 428,961.27, 643,425.72 and 129,433.86

Step by Step Solution

1. Step 1: Write the proportion equation
   428,961.27 : 643,425.72 = 129,433.86 : x
2. Step 2: Convert to fraction form
   428,961.27/643,425.72 = 129,433.86/x
3. Step 3: Cross multiply
   428,961.27x = 643,425.72 × 129,433.86
4. Step 4: Simplify right side
   428,961.27x = 83,281,074,562.88
5. Step 5: Solve for x
   x = 83,281,074,562.88/428,961.27
6. Step 6: Final answer
   x = 194,145.91