Finding the Fourth Proportional to 2,391.38, 3,586.80 and 831.12

Step by Step Solution

1. Step 1: Write the proportion equation
   2,391.38 : 3,586.80 = 831.12 : x
2. Step 2: Convert to fraction form
   2,391.38/3,586.80 = 831.12/x
3. Step 3: Cross multiply
   2,391.38x = 3,586.80 × 831.12
4. Step 4: Simplify right side
   2,391.38x = 2,981,061.22
5. Step 5: Solve for x
   x = 2,981,061.22/2,391.38
6. Step 6: Final answer
   x = 1,246.59