Finding the Fourth Proportional to 1,078.50, 1,487.76 and 685.10

Step by Step Solution

1. Step 1: Write the proportion equation
   1,078.50 : 1,487.76 = 685.10 : x
2. Step 2: Convert to fraction form
   1,078.50/1,487.76 = 685.10/x
3. Step 3: Cross multiply
   1,078.50x = 1,487.76 × 685.10
4. Step 4: Simplify right side
   1,078.50x = 1,019,264.38
5. Step 5: Solve for x
   x = 1,019,264.38/1,078.50
6. Step 6: Final answer
   x = 945.08