Finding the Fourth Proportional to 1,020.84, 1,408.57 and 578.61

Step by Step Solution

1. Step 1: Write the proportion equation
   1,020.84 : 1,408.57 = 578.61 : x
2. Step 2: Convert to fraction form
   1,020.84/1,408.57 = 578.61/x
3. Step 3: Cross multiply
   1,020.84x = 1,408.57 × 578.61
4. Step 4: Simplify right side
   1,020.84x = 815,012.69
5. Step 5: Solve for x
   x = 815,012.69/1,020.84
6. Step 6: Final answer
   x = 798.37