Finding the Fourth Proportional to 1,429.08, 1,971.78 and 831.60

Step by Step Solution

1. Step 1: Write the proportion equation
   1,429.08 : 1,971.78 = 831.60 : x
2. Step 2: Convert to fraction form
   1,429.08/1,971.78 = 831.60/x
3. Step 3: Cross multiply
   1,429.08x = 1,971.78 × 831.60
4. Step 4: Simplify right side
   1,429.08x = 1,639,732.25
5. Step 5: Solve for x
   x = 1,639,732.25/1,429.08
6. Step 6: Final answer
   x = 1,147.40