Finding the Fourth Proportional to 1,020.30, 1,408.27 and 578.47

Step by Step Solution

1. Step 1: Write the proportion equation
   1,020.30 : 1,408.27 = 578.47 : x
2. Step 2: Convert to fraction form
   1,020.30/1,408.27 = 578.47/x
3. Step 3: Cross multiply
   1,020.30x = 1,408.27 × 578.47
4. Step 4: Simplify right side
   1,020.30x = 814,634.91
5. Step 5: Solve for x
   x = 814,634.91/1,020.30
6. Step 6: Final answer
   x = 798.43