Finding the Fourth Proportional to 12,406.80, 17,117.82 and 7,686.12

Step by Step Solution

1. Step 1: Write the proportion equation
   12,406.80 : 17,117.82 = 7,686.12 : x
2. Step 2: Convert to fraction form
   12,406.80/17,117.82 = 7,686.12/x
3. Step 3: Cross multiply
   12,406.80x = 17,117.82 × 7,686.12
4. Step 4: Simplify right side
   12,406.80x = 131,569,618.66
5. Step 5: Solve for x
   x = 131,569,618.66/12,406.80
6. Step 6: Final answer
   x = 10,604.64