Finding the Fourth Proportional to 12,161.80, 18,240.42 and 5,139.52

Step by Step Solution

1. Step 1: Write the proportion equation
   12,161.80 : 18,240.42 = 5,139.52 : x
2. Step 2: Convert to fraction form
   12,161.80/18,240.42 = 5,139.52/x
3. Step 3: Cross multiply
   12,161.80x = 18,240.42 × 5,139.52
4. Step 4: Simplify right side
   12,161.80x = 93,747,003.40
5. Step 5: Solve for x
   x = 93,747,003.40/12,161.80
6. Step 6: Final answer
   x = 7,708.32