Finding the Fourth Proportional to 428,959.27, 643,422.72 and 129,431.86

Step by Step Solution

1. Step 1: Write the proportion equation
   428,959.27 : 643,422.72 = 129,431.86 : x
2. Step 2: Convert to fraction form
   428,959.27/643,422.72 = 129,431.86/x
3. Step 3: Cross multiply
   428,959.27x = 643,422.72 × 129,431.86
4. Step 4: Simplify right side
   428,959.27x = 83,279,399,415.86
5. Step 5: Solve for x
   x = 83,279,399,415.86/428,959.27
6. Step 6: Final answer
   x = 194,142.91