Finding the Fourth Proportional to 12,139.80, 16,371.42 and 12,139.80

Step by Step Solution

1. Step 1: Write the proportion equation
   12,139.80 : 16,371.42 = 12,139.80 : x
2. Step 2: Convert to fraction form
   12,139.80/16,371.42 = 12,139.80/x
3. Step 3: Cross multiply
   12,139.80x = 16,371.42 × 12,139.80
4. Step 4: Simplify right side
   12,139.80x = 198,745,764.52
5. Step 5: Solve for x
   x = 198,745,764.52/12,139.80
6. Step 6: Final answer
   x = 16,371.42