Finding the Fourth Proportional to 72,469.78, 99,892.60 and 57,131.31

Step by Step Solution

1. Step 1: Write the proportion equation
   72,469.78 : 99,892.60 = 57,131.31 : x
2. Step 2: Convert to fraction form
   72,469.78/99,892.60 = 57,131.31/x
3. Step 3: Cross multiply
   72,469.78x = 99,892.60 × 57,131.31
4. Step 4: Simplify right side
   72,469.78x = 5,706,995,097.31
5. Step 5: Solve for x
   x = 5,706,995,097.31/72,469.78
6. Step 6: Final answer
   x = 78,750.00