Finding the Fourth Proportional to 1,870.55, 2,806.77 and 831.23

Step by Step Solution

1. Step 1: Write the proportion equation
   1,870.55 : 2,806.77 = 831.23 : x
2. Step 2: Convert to fraction form
   1,870.55/2,806.77 = 831.23/x
3. Step 3: Cross multiply
   1,870.55x = 2,806.77 × 831.23
4. Step 4: Simplify right side
   1,870.55x = 2,333,071.43
5. Step 5: Solve for x
   x = 2,333,071.43/1,870.55
6. Step 6: Final answer
   x = 1,247.26