Finding the Fourth Proportional to 9,413.78, 12,990.69 and 5,222.42

Step by Step Solution

1. Step 1: Write the proportion equation
   9,413.78 : 12,990.69 = 5,222.42 : x
2. Step 2: Convert to fraction form
   9,413.78/12,990.69 = 5,222.42/x
3. Step 3: Cross multiply
   9,413.78x = 12,990.69 × 5,222.42
4. Step 4: Simplify right side
   9,413.78x = 67,842,839.27
5. Step 5: Solve for x
   x = 67,842,839.27/9,413.78
6. Step 6: Final answer
   x = 7,206.76