Finding the Fourth Proportional to 1,020.56, 1,408.30 and 578.43

Step by Step Solution

1. Step 1: Write the proportion equation
   1,020.56 : 1,408.30 = 578.43 : x
2. Step 2: Convert to fraction form
   1,020.56/1,408.30 = 578.43/x
3. Step 3: Cross multiply
   1,020.56x = 1,408.30 × 578.43
4. Step 4: Simplify right side
   1,020.56x = 814,601.52
5. Step 5: Solve for x
   x = 814,601.52/1,020.56
6. Step 6: Final answer
   x = 798.19