Finding the Fourth Proportional to 1,078.81, 1,618.52 and 385.55

Step by Step Solution

1. Step 1: Write the proportion equation
   1,078.81 : 1,618.52 = 385.55 : x
2. Step 2: Convert to fraction form
   1,078.81/1,618.52 = 385.55/x
3. Step 3: Cross multiply
   1,078.81x = 1,618.52 × 385.55
4. Step 4: Simplify right side
   1,078.81x = 624,020.39
5. Step 5: Solve for x
   x = 624,020.39/1,078.81
6. Step 6: Final answer
   x = 578.43