Finding the Fourth Proportional to 656,309, 905,706.78 and 354,503

Step by Step Solution

1. Step 1: Write the proportion equation
   656,309 : 905,706.78 = 354,503 : x
2. Step 2: Convert to fraction form
   656,309/905,706.78 = 354,503/x
3. Step 3: Cross multiply
   656,309x = 905,706.78 × 354,503
4. Step 4: Simplify right side
   656,309x = 321,075,770,630.34
5. Step 5: Solve for x
   x = 321,075,770,630.34/656,309
6. Step 6: Final answer
   x = 489,214.33