Finding the Fourth Proportional to 1,020.55, 1,408.42 and 578.47

Step by Step Solution

1. Step 1: Write the proportion equation
   1,020.55 : 1,408.42 = 578.47 : x
2. Step 2: Convert to fraction form
   1,020.55/1,408.42 = 578.47/x
3. Step 3: Cross multiply
   1,020.55x = 1,408.42 × 578.47
4. Step 4: Simplify right side
   1,020.55x = 814,728.72
5. Step 5: Solve for x
   x = 814,728.72/1,020.55
6. Step 6: Final answer
   x = 798.32