Finding the Fourth Proportional to 3,612.59, 5,413.69 and 2,128.31

Step by Step Solution

1. Step 1: Write the proportion equation
   3,612.59 : 5,413.69 = 2,128.31 : x
2. Step 2: Convert to fraction form
   3,612.59/5,413.69 = 2,128.31/x
3. Step 3: Cross multiply
   3,612.59x = 5,413.69 × 2,128.31
4. Step 4: Simplify right side
   3,612.59x = 11,522,018.78
5. Step 5: Solve for x
   x = 11,522,018.78/3,612.59
6. Step 6: Final answer
   x = 3,189.40