Finding the Fourth Proportional to 1,020.31, 1,408.04 and 554.56

Step by Step Solution

1. Step 1: Write the proportion equation
   1,020.31 : 1,408.04 = 554.56 : x
2. Step 2: Convert to fraction form
   1,020.31/1,408.04 = 554.56/x
3. Step 3: Cross multiply
   1,020.31x = 1,408.04 × 554.56
4. Step 4: Simplify right side
   1,020.31x = 780,842.66
5. Step 5: Solve for x
   x = 780,842.66/1,020.31
6. Step 6: Final answer
   x = 765.30