Finding the Fourth Proportional to 1,355.72, 1,870.98 and 831.68

Step by Step Solution

1. Step 1: Write the proportion equation
   1,355.72 : 1,870.98 = 831.68 : x
2. Step 2: Convert to fraction form
   1,355.72/1,870.98 = 831.68/x
3. Step 3: Cross multiply
   1,355.72x = 1,870.98 × 831.68
4. Step 4: Simplify right side
   1,355.72x = 1,556,056.65
5. Step 5: Solve for x
   x = 1,556,056.65/1,355.72
6. Step 6: Final answer
   x = 1,147.77