Finding the Fourth Proportional to 21,864.55, 30,167.89 and 12,438.31

Step by Step Solution

1. Step 1: Write the proportion equation
   21,864.55 : 30,167.89 = 12,438.31 : x
2. Step 2: Convert to fraction form
   21,864.55/30,167.89 = 12,438.31/x
3. Step 3: Cross multiply
   21,864.55x = 30,167.89 × 12,438.31
4. Step 4: Simplify right side
   21,864.55x = 375,237,567.87
5. Step 5: Solve for x
   x = 375,237,567.87/21,864.55
6. Step 6: Final answer
   x = 17,161.92