Finding the Fourth Proportional to 1,078.43, 1,487.70 and 685.58

Step by Step Solution

1. Step 1: Write the proportion equation
   1,078.43 : 1,487.70 = 685.58 : x
2. Step 2: Convert to fraction form
   1,078.43/1,487.70 = 685.58/x
3. Step 3: Cross multiply
   1,078.43x = 1,487.70 × 685.58
4. Step 4: Simplify right side
   1,078.43x = 1,019,929.93
5. Step 5: Solve for x
   x = 1,019,929.93/1,078.43
6. Step 6: Final answer
   x = 945.76