Finding the Fourth Proportional to 9,399.99, 12,972.18 and 5,815.47

Step by Step Solution

1. Step 1: Write the proportion equation
   9,399.99 : 12,972.18 = 5,815.47 : x
2. Step 2: Convert to fraction form
   9,399.99/12,972.18 = 5,815.47/x
3. Step 3: Cross multiply
   9,399.99x = 12,972.18 × 5,815.47
4. Step 4: Simplify right side
   9,399.99x = 75,439,323.62
5. Step 5: Solve for x
   x = 75,439,323.62/9,399.99
6. Step 6: Final answer
   x = 8,025.47