Finding the Fourth Proportional to 1,355.50, 1,870.64 and 831.43

Step by Step Solution

1. Step 1: Write the proportion equation
   1,355.50 : 1,870.64 = 831.43 : x
2. Step 2: Convert to fraction form
   1,355.50/1,870.64 = 831.43/x
3. Step 3: Cross multiply
   1,355.50x = 1,870.64 × 831.43
4. Step 4: Simplify right side
   1,355.50x = 1,555,306.22
5. Step 5: Solve for x
   x = 1,555,306.22/1,355.50
6. Step 6: Final answer
   x = 1,147.40