Finding the Fourth Proportional to 2,586.17, 3,879.89 and 831.33

Step by Step Solution

1. Step 1: Write the proportion equation
   2,586.17 : 3,879.89 = 831.33 : x
2. Step 2: Convert to fraction form
   2,586.17/3,879.89 = 831.33/x
3. Step 3: Cross multiply
   2,586.17x = 3,879.89 × 831.33
4. Step 4: Simplify right side
   2,586.17x = 3,225,471.03
5. Step 5: Solve for x
   x = 3,225,471.03/2,586.17
6. Step 6: Final answer
   x = 1,247.20