Finding the Fourth Proportional to 6,413.78, 9,621.86 and 3,125.99

Step by Step Solution

1. Step 1: Write the proportion equation
   6,413.78 : 9,621.86 = 3,125.99 : x
2. Step 2: Convert to fraction form
   6,413.78/9,621.86 = 3,125.99/x
3. Step 3: Cross multiply
   6,413.78x = 9,621.86 × 3,125.99
4. Step 4: Simplify right side
   6,413.78x = 30,077,774.40
5. Step 5: Solve for x
   x = 30,077,774.40/6,413.78
6. Step 6: Final answer
   x = 4,689.56