Finding the Fourth Proportional to 10,086.78, 15,120.45 and 5,158.74

Step by Step Solution

1. Step 1: Write the proportion equation
   10,086.78 : 15,120.45 = 5,158.74 : x
2. Step 2: Convert to fraction form
   10,086.78/15,120.45 = 5,158.74/x
3. Step 3: Cross multiply
   10,086.78x = 15,120.45 × 5,158.74
4. Step 4: Simplify right side
   10,086.78x = 78,002,470.23
5. Step 5: Solve for x
   x = 78,002,470.23/10,086.78
6. Step 6: Final answer
   x = 7,733.14