Finding the Fourth Proportional to 12,320.96, 18,453.67 and 8,639.61

Step by Step Solution

1. Step 1: Write the proportion equation
   12,320.96 : 18,453.67 = 8,639.61 : x
2. Step 2: Convert to fraction form
   12,320.96/18,453.67 = 8,639.61/x
3. Step 3: Cross multiply
   12,320.96x = 18,453.67 × 8,639.61
4. Step 4: Simplify right side
   12,320.96x = 159,432,573.47
5. Step 5: Solve for x
   x = 159,432,573.47/12,320.96
6. Step 6: Final answer
   x = 12,939.95