Finding the Fourth Proportional to 1,078.47, 1,488.50 and 685.95

Step by Step Solution

1. Step 1: Write the proportion equation
   1,078.47 : 1,488.50 = 685.95 : x
2. Step 2: Convert to fraction form
   1,078.47/1,488.50 = 685.95/x
3. Step 3: Cross multiply
   1,078.47x = 1,488.50 × 685.95
4. Step 4: Simplify right side
   1,078.47x = 1,021,033.15
5. Step 5: Solve for x
   x = 1,021,033.15/1,078.47
6. Step 6: Final answer
   x = 946.74