Finding the Fourth Proportional to 1,078.64, 1,488.30 and 685.52

Step by Step Solution

1. Step 1: Write the proportion equation
   1,078.64 : 1,488.30 = 685.52 : x
2. Step 2: Convert to fraction form
   1,078.64/1,488.30 = 685.52/x
3. Step 3: Cross multiply
   1,078.64x = 1,488.30 × 685.52
4. Step 4: Simplify right side
   1,078.64x = 1,020,259.42
5. Step 5: Solve for x
   x = 1,020,259.42/1,078.64
6. Step 6: Final answer
   x = 945.88