Finding the Fourth Proportional to 1,413.20, 1,949.96 and 815.55

Step by Step Solution

1. Step 1: Write the proportion equation
   1,413.20 : 1,949.96 = 815.55 : x
2. Step 2: Convert to fraction form
   1,413.20/1,949.96 = 815.55/x
3. Step 3: Cross multiply
   1,413.20x = 1,949.96 × 815.55
4. Step 4: Simplify right side
   1,413.20x = 1,590,285.80
5. Step 5: Solve for x
   x = 1,590,285.80/1,413.20
6. Step 6: Final answer
   x = 1,125.31