Finding the Fourth Proportional to 12,689.47, 17,513.55 and 8,707.31

Step by Step Solution

1. Step 1: Write the proportion equation
   12,689.47 : 17,513.55 = 8,707.31 : x
2. Step 2: Convert to fraction form
   12,689.47/17,513.55 = 8,707.31/x
3. Step 3: Cross multiply
   12,689.47x = 17,513.55 × 8,707.31
4. Step 4: Simplify right side
   12,689.47x = 152,495,909.05
5. Step 5: Solve for x
   x = 152,495,909.05/12,689.47
6. Step 6: Final answer
   x = 12,017.52