Finding the Fourth Proportional to 619,761.28, 855,298.56 and 485,392

Step by Step Solution

1. Step 1: Write the proportion equation
   619,761.28 : 855,298.56 = 485,392 : x
2. Step 2: Convert to fraction form
   619,761.28/855,298.56 = 485,392/x
3. Step 3: Cross multiply
   619,761.28x = 855,298.56 × 485,392
4. Step 4: Simplify right side
   619,761.28x = 415,155,078,635.52
5. Step 5: Solve for x
   x = 415,155,078,635.52/619,761.28
6. Step 6: Final answer
   x = 669,862.88