Finding the Fourth Proportional to 12,456.79, 18,648.12 and 12,440.39

Step by Step Solution

1. Step 1: Write the proportion equation
   12,456.79 : 18,648.12 = 12,440.39 : x
2. Step 2: Convert to fraction form
   12,456.79/18,648.12 = 12,440.39/x
3. Step 3: Cross multiply
   12,456.79x = 18,648.12 × 12,440.39
4. Step 4: Simplify right side
   12,456.79x = 231,989,838.98
5. Step 5: Solve for x
   x = 231,989,838.98/12,456.79
6. Step 6: Final answer
   x = 18,623.57