Finding the Fourth Proportional to 1,013.78, 1,399.03 and 571.59

Step by Step Solution

1. Step 1: Write the proportion equation
   1,013.78 : 1,399.03 = 571.59 : x
2. Step 2: Convert to fraction form
   1,013.78/1,399.03 = 571.59/x
3. Step 3: Cross multiply
   1,013.78x = 1,399.03 × 571.59
4. Step 4: Simplify right side
   1,013.78x = 799,680.05
5. Step 5: Solve for x
   x = 799,680.05/1,013.78
6. Step 6: Final answer
   x = 788.81