Finding the Fourth Proportional to 419,456.58, 578,976.57 and 285,398.34

Step by Step Solution

1. Step 1: Write the proportion equation
   419,456.58 : 578,976.57 = 285,398.34 : x
2. Step 2: Convert to fraction form
   419,456.58/578,976.57 = 285,398.34/x
3. Step 3: Cross multiply
   419,456.58x = 578,976.57 × 285,398.34
4. Step 4: Simplify right side
   419,456.58x = 165,238,951,976.89
5. Step 5: Solve for x
   x = 165,238,951,976.89/419,456.58
6. Step 6: Final answer
   x = 393,935.77