Finding the Fourth Proportional to 9,413.28, 12,990.72 and 5,221.56

Step by Step Solution

1. Step 1: Write the proportion equation
   9,413.28 : 12,990.72 = 5,221.56 : x
2. Step 2: Convert to fraction form
   9,413.28/12,990.72 = 5,221.56/x
3. Step 3: Cross multiply
   9,413.28x = 12,990.72 × 5,221.56
4. Step 4: Simplify right side
   9,413.28x = 67,831,823.92
5. Step 5: Solve for x
   x = 67,831,823.92/9,413.28
6. Step 6: Final answer
   x = 7,205.97