Finding the Fourth Proportional to 12,399.75, 17,113.28 and 8,620.83

Step by Step Solution

1. Step 1: Write the proportion equation
   12,399.75 : 17,113.28 = 8,620.83 : x
2. Step 2: Convert to fraction form
   12,399.75/17,113.28 = 8,620.83/x
3. Step 3: Cross multiply
   12,399.75x = 17,113.28 × 8,620.83
4. Step 4: Simplify right side
   12,399.75x = 147,530,634.52
5. Step 5: Solve for x
   x = 147,530,634.52/12,399.75
6. Step 6: Final answer
   x = 11,897.87