Finding the Fourth Proportional to 1,020.78, 1,529.55 and 558.54

Step by Step Solution

1. Step 1: Write the proportion equation
   1,020.78 : 1,529.55 = 558.54 : x
2. Step 2: Convert to fraction form
   1,020.78/1,529.55 = 558.54/x
3. Step 3: Cross multiply
   1,020.78x = 1,529.55 × 558.54
4. Step 4: Simplify right side
   1,020.78x = 854,314.86
5. Step 5: Solve for x
   x = 854,314.86/1,020.78
6. Step 6: Final answer
   x = 836.92