Finding the Fourth Proportional to 1,355.62, 1,870.79 and 831.35

Step by Step Solution

1. Step 1: Write the proportion equation
   1,355.62 : 1,870.79 = 831.35 : x
2. Step 2: Convert to fraction form
   1,355.62/1,870.79 = 831.35/x
3. Step 3: Cross multiply
   1,355.62x = 1,870.79 × 831.35
4. Step 4: Simplify right side
   1,355.62x = 1,555,281.27
5. Step 5: Solve for x
   x = 1,555,281.27/1,355.62
6. Step 6: Final answer
   x = 1,147.28