Finding the Fourth Proportional to 13,139.82, 18,128.61 and 8,665.79

Step by Step Solution

1. Step 1: Write the proportion equation
   13,139.82 : 18,128.61 = 8,665.79 : x
2. Step 2: Convert to fraction form
   13,139.82/18,128.61 = 8,665.79/x
3. Step 3: Cross multiply
   13,139.82x = 18,128.61 × 8,665.79
4. Step 4: Simplify right side
   13,139.82x = 157,098,636.61
5. Step 5: Solve for x
   x = 157,098,636.61/13,139.82
6. Step 6: Final answer
   x = 11,955.92