Finding the Fourth Proportional to 12,925.50, 19,399.32 and 5,139.78

Step by Step Solution

1. Step 1: Write the proportion equation
   12,925.50 : 19,399.32 = 5,139.78 : x
2. Step 2: Convert to fraction form
   12,925.50/19,399.32 = 5,139.78/x
3. Step 3: Cross multiply
   12,925.50x = 19,399.32 × 5,139.78
4. Step 4: Simplify right side
   12,925.50x = 99,708,236.95
5. Step 5: Solve for x
   x = 99,708,236.95/12,925.50
6. Step 6: Final answer
   x = 7,714.07