Finding the Fourth Proportional to 644,994.32, 890,069.46 and 354,603.78

Step by Step Solution

1. Step 1: Write the proportion equation
   644,994.32 : 890,069.46 = 354,603.78 : x
2. Step 2: Convert to fraction form
   644,994.32/890,069.46 = 354,603.78/x
3. Step 3: Cross multiply
   644,994.32x = 890,069.46 × 354,603.78
4. Step 4: Simplify right side
   644,994.32x = 315,621,994,978.56
5. Step 5: Solve for x
   x = 315,621,994,978.56/644,994.32
6. Step 6: Final answer
   x = 489,340.74