Finding the Fourth Proportional to 969.91, 1,456.72 and 831.40

Step by Step Solution

1. Step 1: Write the proportion equation
   969.91 : 1,456.72 = 831.40 : x
2. Step 2: Convert to fraction form
   969.91/1,456.72 = 831.40/x
3. Step 3: Cross multiply
   969.91x = 1,456.72 × 831.40
4. Step 4: Simplify right side
   969.91x = 1,211,111.80
5. Step 5: Solve for x
   x = 1,211,111.80/969.91
6. Step 6: Final answer
   x = 1,248.69