Finding the Fourth Proportional to 1,223.72, 1,831.12 and 812.24

Step by Step Solution

1. Step 1: Write the proportion equation
   1,223.72 : 1,831.12 = 812.24 : x
2. Step 2: Convert to fraction form
   1,223.72/1,831.12 = 812.24/x
3. Step 3: Cross multiply
   1,223.72x = 1,831.12 × 812.24
4. Step 4: Simplify right side
   1,223.72x = 1,487,308.91
5. Step 5: Solve for x
   x = 1,487,308.91/1,223.72
6. Step 6: Final answer
   x = 1,215.40