Finding the Fourth Proportional to 9,222.29, 12,728.15 and 5,639.31

Step by Step Solution

1. Step 1: Write the proportion equation
   9,222.29 : 12,728.15 = 5,639.31 : x
2. Step 2: Convert to fraction form
   9,222.29/12,728.15 = 5,639.31/x
3. Step 3: Cross multiply
   9,222.29x = 12,728.15 × 5,639.31
4. Step 4: Simplify right side
   9,222.29x = 71,777,983.58
5. Step 5: Solve for x
   x = 71,777,983.58/9,222.29
6. Step 6: Final answer
   x = 7,783.10