Finding the Fourth Proportional to 12,499.12, 18,638.44 and 12,386.61

Step by Step Solution

1. Step 1: Write the proportion equation
   12,499.12 : 18,638.44 = 12,386.61 : x
2. Step 2: Convert to fraction form
   12,499.12/18,638.44 = 12,386.61/x
3. Step 3: Cross multiply
   12,499.12x = 18,638.44 × 12,386.61
4. Step 4: Simplify right side
   12,499.12x = 230,866,932.16
5. Step 5: Solve for x
   x = 230,866,932.16/12,499.12
6. Step 6: Final answer
   x = 18,470.65