Finding the Fourth Proportional to 2,146.86, 3,220.16 and 685.89

Step by Step Solution

1. Step 1: Write the proportion equation
   2,146.86 : 3,220.16 = 685.89 : x
2. Step 2: Convert to fraction form
   2,146.86/3,220.16 = 685.89/x
3. Step 3: Cross multiply
   2,146.86x = 3,220.16 × 685.89
4. Step 4: Simplify right side
   2,146.86x = 2,208,672.11
5. Step 5: Solve for x
   x = 2,208,672.11/2,146.86
6. Step 6: Final answer
   x = 1,028.79