Finding the Fourth Proportional to 21,002.39, 31,485.61 and 9,147.13

Step by Step Solution

1. Step 1: Write the proportion equation
   21,002.39 : 31,485.61 = 9,147.13 : x
2. Step 2: Convert to fraction form
   21,002.39/31,485.61 = 9,147.13/x
3. Step 3: Cross multiply
   21,002.39x = 31,485.61 × 9,147.13
4. Step 4: Simplify right side
   21,002.39x = 288,002,900.52
5. Step 5: Solve for x
   x = 288,002,900.52/21,002.39
6. Step 6: Final answer
   x = 13,712.86