Finding the Fourth Proportional to 1,225.24, 1,688.91 and 831.58

Step by Step Solution

1. Step 1: Write the proportion equation
   1,225.24 : 1,688.91 = 831.58 : x
2. Step 2: Convert to fraction form
   1,225.24/1,688.91 = 831.58/x
3. Step 3: Cross multiply
   1,225.24x = 1,688.91 × 831.58
4. Step 4: Simplify right side
   1,225.24x = 1,404,463.78
5. Step 5: Solve for x
   x = 1,404,463.78/1,225.24
6. Step 6: Final answer
   x = 1,146.28