Finding the Fourth Proportional to 2,280.88, 3,420.72 and 819.76

Step by Step Solution

1. Step 1: Write the proportion equation
   2,280.88 : 3,420.72 = 819.76 : x
2. Step 2: Convert to fraction form
   2,280.88/3,420.72 = 819.76/x
3. Step 3: Cross multiply
   2,280.88x = 3,420.72 × 819.76
4. Step 4: Simplify right side
   2,280.88x = 2,804,169.43
5. Step 5: Solve for x
   x = 2,804,169.43/2,280.88
6. Step 6: Final answer
   x = 1,229.42