Finding the Fourth Proportional to 21,348.89, 29,456.89 and 12,391.61

Step by Step Solution

1. Step 1: Write the proportion equation
   21,348.89 : 29,456.89 = 12,391.61 : x
2. Step 2: Convert to fraction form
   21,348.89/29,456.89 = 12,391.61/x
3. Step 3: Cross multiply
   21,348.89x = 29,456.89 × 12,391.61
4. Step 4: Simplify right side
   21,348.89x = 365,018,292.69
5. Step 5: Solve for x
   x = 365,018,292.69/21,348.89
6. Step 6: Final answer
   x = 17,097.76