Finding the Fourth Proportional to 9,321.30, 12,863.16 and 5,072.31

Step by Step Solution

1. Step 1: Write the proportion equation
   9,321.30 : 12,863.16 = 5,072.31 : x
2. Step 2: Convert to fraction form
   9,321.30/12,863.16 = 5,072.31/x
3. Step 3: Cross multiply
   9,321.30x = 12,863.16 × 5,072.31
4. Step 4: Simplify right side
   9,321.30x = 65,245,935.10
5. Step 5: Solve for x
   x = 65,245,935.10/9,321.30
6. Step 6: Final answer
   x = 6,999.66