Finding the Fourth Proportional to 2,280.48, 3,420.78 and 819.78

Step by Step Solution

1. Step 1: Write the proportion equation
   2,280.48 : 3,420.78 = 819.78 : x
2. Step 2: Convert to fraction form
   2,280.48/3,420.78 = 819.78/x
3. Step 3: Cross multiply
   2,280.48x = 3,420.78 × 819.78
4. Step 4: Simplify right side
   2,280.48x = 2,804,287.03
5. Step 5: Solve for x
   x = 2,804,287.03/2,280.48
6. Step 6: Final answer
   x = 1,229.69