Finding the Fourth Proportional to 12,687.12, 17,498.88 and 8,708.40

Step by Step Solution

1. Step 1: Write the proportion equation
   12,687.12 : 17,498.88 = 8,708.40 : x
2. Step 2: Convert to fraction form
   12,687.12/17,498.88 = 8,708.40/x
3. Step 3: Cross multiply
   12,687.12x = 17,498.88 × 8,708.40
4. Step 4: Simplify right side
   12,687.12x = 152,387,246.59
5. Step 5: Solve for x
   x = 152,387,246.59/12,687.12
6. Step 6: Final answer
   x = 12,011.18