Finding the Fourth Proportional to 1,020.80, 1,408.73 and 555.05

Step by Step Solution

1. Step 1: Write the proportion equation
   1,020.80 : 1,408.73 = 555.05 : x
2. Step 2: Convert to fraction form
   1,020.80/1,408.73 = 555.05/x
3. Step 3: Cross multiply
   1,020.80x = 1,408.73 × 555.05
4. Step 4: Simplify right side
   1,020.80x = 781,916.33
5. Step 5: Solve for x
   x = 781,916.33/1,020.80
6. Step 6: Final answer
   x = 765.98