Finding the Fourth Proportional to 690,680, 1,036,168.20 and 391,304

Step by Step Solution

1. Step 1: Write the proportion equation
   690,680 : 1,036,168.20 = 391,304 : x
2. Step 2: Convert to fraction form
   690,680/1,036,168.20 = 391,304/x
3. Step 3: Cross multiply
   690,680x = 1,036,168.20 × 391,304
4. Step 4: Simplify right side
   690,680x = 405,456,761,332.80
5. Step 5: Solve for x
   x = 405,456,761,332.80/690,680
6. Step 6: Final answer
   x = 587,039.96