Finding the Fourth Proportional to 12,925.20, 19,391.40 and 5,139.48

Step by Step Solution

1. Step 1: Write the proportion equation
   12,925.20 : 19,391.40 = 5,139.48 : x
2. Step 2: Convert to fraction form
   12,925.20/19,391.40 = 5,139.48/x
3. Step 3: Cross multiply
   12,925.20x = 19,391.40 × 5,139.48
4. Step 4: Simplify right side
   12,925.20x = 99,661,712.47
5. Step 5: Solve for x
   x = 99,661,712.47/12,925.20
6. Step 6: Final answer
   x = 7,710.65