Finding the Fourth Proportional to 1,008.56, 1,391.91 and 560.58

Step by Step Solution

1. Step 1: Write the proportion equation
   1,008.56 : 1,391.91 = 560.58 : x
2. Step 2: Convert to fraction form
   1,008.56/1,391.91 = 560.58/x
3. Step 3: Cross multiply
   1,008.56x = 1,391.91 × 560.58
4. Step 4: Simplify right side
   1,008.56x = 780,269.59
5. Step 5: Solve for x
   x = 780,269.59/1,008.56
6. Step 6: Final answer
   x = 773.65