Finding the Fourth Proportional to 10,089.78, 15,120.81 and 5,149.05

Step by Step Solution

1. Step 1: Write the proportion equation
   10,089.78 : 15,120.81 = 5,149.05 : x
2. Step 2: Convert to fraction form
   10,089.78/15,120.81 = 5,149.05/x
3. Step 3: Cross multiply
   10,089.78x = 15,120.81 × 5,149.05
4. Step 4: Simplify right side
   10,089.78x = 77,857,806.73
5. Step 5: Solve for x
   x = 77,857,806.73/10,089.78
6. Step 6: Final answer
   x = 7,716.50