Finding the Fourth Proportional to 1,008.55, 1,391.72 and 560.42

Step by Step Solution

1. Step 1: Write the proportion equation
   1,008.55 : 1,391.72 = 560.42 : x
2. Step 2: Convert to fraction form
   1,008.55/1,391.72 = 560.42/x
3. Step 3: Cross multiply
   1,008.55x = 1,391.72 × 560.42
4. Step 4: Simplify right side
   1,008.55x = 779,943.18
5. Step 5: Solve for x
   x = 779,943.18/1,008.55
6. Step 6: Final answer
   x = 773.33