Finding the Fourth Proportional to 1,078.66, 1,488.72 and 685.81

Step by Step Solution

1. Step 1: Write the proportion equation
   1,078.66 : 1,488.72 = 685.81 : x
2. Step 2: Convert to fraction form
   1,078.66/1,488.72 = 685.81/x
3. Step 3: Cross multiply
   1,078.66x = 1,488.72 × 685.81
4. Step 4: Simplify right side
   1,078.66x = 1,020,979.06
5. Step 5: Solve for x
   x = 1,020,979.06/1,078.66
6. Step 6: Final answer
   x = 946.53