Finding the Fourth Proportional to 21,400.59, 29,542.27 and 12,789.81

Step by Step Solution

1. Step 1: Write the proportion equation
   21,400.59 : 29,542.27 = 12,789.81 : x
2. Step 2: Convert to fraction form
   21,400.59/29,542.27 = 12,789.81/x
3. Step 3: Cross multiply
   21,400.59x = 29,542.27 × 12,789.81
4. Step 4: Simplify right side
   21,400.59x = 377,840,020.27
5. Step 5: Solve for x
   x = 377,840,020.27/21,400.59
6. Step 6: Final answer
   x = 17,655.59