Finding the Fourth Proportional to 1,008.20, 1,391.31 and 566.10

Step by Step Solution

1. Step 1: Write the proportion equation
   1,008.20 : 1,391.31 = 566.10 : x
2. Step 2: Convert to fraction form
   1,008.20/1,391.31 = 566.10/x
3. Step 3: Cross multiply
   1,008.20x = 1,391.31 × 566.10
4. Step 4: Simplify right side
   1,008.20x = 787,620.59
5. Step 5: Solve for x
   x = 787,620.59/1,008.20
6. Step 6: Final answer
   x = 781.21