Finding the Fourth Proportional to 1,078.84, 1,488.54 and 685.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,078.84 : 1,488.54 = 685.72 : x
2. Step 2: Convert to fraction form
   1,078.84/1,488.54 = 685.72/x
3. Step 3: Cross multiply
   1,078.84x = 1,488.54 × 685.72
4. Step 4: Simplify right side
   1,078.84x = 1,020,721.65
5. Step 5: Solve for x
   x = 1,020,721.65/1,078.84
6. Step 6: Final answer
   x = 946.13