Finding the Fourth Proportional to 9,120.79, 12,571.54 and 7,229.04

Step by Step Solution

1. Step 1: Write the proportion equation
   9,120.79 : 12,571.54 = 7,229.04 : x
2. Step 2: Convert to fraction form
   9,120.79/12,571.54 = 7,229.04/x
3. Step 3: Cross multiply
   9,120.79x = 12,571.54 × 7,229.04
4. Step 4: Simplify right side
   9,120.79x = 90,880,165.52
5. Step 5: Solve for x
   x = 90,880,165.52/9,120.79
6. Step 6: Final answer
   x = 9,964.07