Finding the Fourth Proportional to 9,321.06, 12,863.07 and 5,129.31

Step by Step Solution

1. Step 1: Write the proportion equation
   9,321.06 : 12,863.07 = 5,129.31 : x
2. Step 2: Convert to fraction form
   9,321.06/12,863.07 = 5,129.31/x
3. Step 3: Cross multiply
   9,321.06x = 12,863.07 × 5,129.31
4. Step 4: Simplify right side
   9,321.06x = 65,978,673.58
5. Step 5: Solve for x
   x = 65,978,673.58/9,321.06
6. Step 6: Final answer
   x = 7,078.45