Finding the Fourth Proportional to 8,442.50, 11,642.86 and 7,771.78

Step by Step Solution

1. Step 1: Write the proportion equation
   8,442.50 : 11,642.86 = 7,771.78 : x
2. Step 2: Convert to fraction form
   8,442.50/11,642.86 = 7,771.78/x
3. Step 3: Cross multiply
   8,442.50x = 11,642.86 × 7,771.78
4. Step 4: Simplify right side
   8,442.50x = 90,485,792.62
5. Step 5: Solve for x
   x = 90,485,792.62/8,442.50
6. Step 6: Final answer
   x = 10,717.90