Finding the Fourth Proportional to 1,024.56, 1,535.94 and 408.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,024.56 : 1,535.94 = 408.78 : x
2. Step 2: Convert to fraction form
   1,024.56/1,535.94 = 408.78/x
3. Step 3: Cross multiply
   1,024.56x = 1,535.94 × 408.78
4. Step 4: Simplify right side
   1,024.56x = 627,861.55
5. Step 5: Solve for x
   x = 627,861.55/1,024.56
6. Step 6: Final answer
   x = 612.81