Finding the Fourth Proportional to 641,620.49, 885,343.59 and 355,139.89

Step by Step Solution

1. Step 1: Write the proportion equation
   641,620.49 : 885,343.59 = 355,139.89 : x
2. Step 2: Convert to fraction form
   641,620.49/885,343.59 = 355,139.89/x
3. Step 3: Cross multiply
   641,620.49x = 885,343.59 × 355,139.89
4. Step 4: Simplify right side
   641,620.49x = 314,420,822,951.45
5. Step 5: Solve for x
   x = 314,420,822,951.45/641,620.49
6. Step 6: Final answer
   x = 490,041.75