Finding the Fourth Proportional to 1,355.30, 1,870.56 and 831.26

Step by Step Solution

1. Step 1: Write the proportion equation
   1,355.30 : 1,870.56 = 831.26 : x
2. Step 2: Convert to fraction form
   1,355.30/1,870.56 = 831.26/x
3. Step 3: Cross multiply
   1,355.30x = 1,870.56 × 831.26
4. Step 4: Simplify right side
   1,355.30x = 1,554,921.71
5. Step 5: Solve for x
   x = 1,554,921.71/1,355.30
6. Step 6: Final answer
   x = 1,147.29