Finding the Fourth Proportional to 12,856.98, 19,276.15 and 8,686.56

Step by Step Solution

1. Step 1: Write the proportion equation
   12,856.98 : 19,276.15 = 8,686.56 : x
2. Step 2: Convert to fraction form
   12,856.98/19,276.15 = 8,686.56/x
3. Step 3: Cross multiply
   12,856.98x = 19,276.15 × 8,686.56
4. Step 4: Simplify right side
   12,856.98x = 167,443,433.54
5. Step 5: Solve for x
   x = 167,443,433.54/12,856.98
6. Step 6: Final answer
   x = 13,023.54