Finding the Fourth Proportional to 1,870.11, 2,806.17 and 831.15

Step by Step Solution

1. Step 1: Write the proportion equation
   1,870.11 : 2,806.17 = 831.15 : x
2. Step 2: Convert to fraction form
   1,870.11/2,806.17 = 831.15/x
3. Step 3: Cross multiply
   1,870.11x = 2,806.17 × 831.15
4. Step 4: Simplify right side
   1,870.11x = 2,332,348.20
5. Step 5: Solve for x
   x = 2,332,348.20/1,870.11
6. Step 6: Final answer
   x = 1,247.17