Finding the Fourth Proportional to 12,685.78, 17,504.32 and 7,966.72

Step by Step Solution

1. Step 1: Write the proportion equation
   12,685.78 : 17,504.32 = 7,966.72 : x
2. Step 2: Convert to fraction form
   12,685.78/17,504.32 = 7,966.72/x
3. Step 3: Cross multiply
   12,685.78x = 17,504.32 × 7,966.72
4. Step 4: Simplify right side
   12,685.78x = 139,452,016.23
5. Step 5: Solve for x
   x = 139,452,016.23/12,685.78
6. Step 6: Final answer
   x = 10,992.78