Finding the Fourth Proportional to 12,688.89, 17,508.06 and 8,708.55

Step by Step Solution

1. Step 1: Write the proportion equation
   12,688.89 : 17,508.06 = 8,708.55 : x
2. Step 2: Convert to fraction form
   12,688.89/17,508.06 = 8,708.55/x
3. Step 3: Cross multiply
   12,688.89x = 17,508.06 × 8,708.55
4. Step 4: Simplify right side
   12,688.89x = 152,469,815.91
5. Step 5: Solve for x
   x = 152,469,815.91/12,688.89
6. Step 6: Final answer
   x = 12,016.01