Finding the Fourth Proportional to 8,456.43, 12,687.89 and 3,191.07

Step by Step Solution

1. Step 1: Write the proportion equation
   8,456.43 : 12,687.89 = 3,191.07 : x
2. Step 2: Convert to fraction form
   8,456.43/12,687.89 = 3,191.07/x
3. Step 3: Cross multiply
   8,456.43x = 12,687.89 × 3,191.07
4. Step 4: Simplify right side
   8,456.43x = 40,487,929.19
5. Step 5: Solve for x
   x = 40,487,929.19/8,456.43
6. Step 6: Final answer
   x = 4,787.83