Finding the Fourth Proportional to 9,411.71, 12,990.52 and 6,391.94

Step by Step Solution

1. Step 1: Write the proportion equation
   9,411.71 : 12,990.52 = 6,391.94 : x
2. Step 2: Convert to fraction form
   9,411.71/12,990.52 = 6,391.94/x
3. Step 3: Cross multiply
   9,411.71x = 12,990.52 × 6,391.94
4. Step 4: Simplify right side
   9,411.71x = 83,034,672.86
5. Step 5: Solve for x
   x = 83,034,672.86/9,411.71
6. Step 6: Final answer
   x = 8,822.49