Finding the Fourth Proportional to 1,020.39, 1,408.15 and 578.34

Step by Step Solution

1. Step 1: Write the proportion equation
   1,020.39 : 1,408.15 = 578.34 : x
2. Step 2: Convert to fraction form
   1,020.39/1,408.15 = 578.34/x
3. Step 3: Cross multiply
   1,020.39x = 1,408.15 × 578.34
4. Step 4: Simplify right side
   1,020.39x = 814,389.47
5. Step 5: Solve for x
   x = 814,389.47/1,020.39
6. Step 6: Final answer
   x = 798.12