Finding the Fourth Proportional to 129,089.71, 178,124.48 and 72,490.15

Step by Step Solution

1. Step 1: Write the proportion equation
   129,089.71 : 178,124.48 = 72,490.15 : x
2. Step 2: Convert to fraction form
   129,089.71/178,124.48 = 72,490.15/x
3. Step 3: Cross multiply
   129,089.71x = 178,124.48 × 72,490.15
4. Step 4: Simplify right side
   129,089.71x = 12,912,269,911.42
5. Step 5: Solve for x
   x = 12,912,269,911.42/129,089.71
6. Step 6: Final answer
   x = 100,025.56