Finding the Fourth Proportional to 1,223.40, 1,831.86 and 644.52

Step by Step Solution

1. Step 1: Write the proportion equation
   1,223.40 : 1,831.86 = 644.52 : x
2. Step 2: Convert to fraction form
   1,223.40/1,831.86 = 644.52/x
3. Step 3: Cross multiply
   1,223.40x = 1,831.86 × 644.52
4. Step 4: Simplify right side
   1,223.40x = 1,180,670.41
5. Step 5: Solve for x
   x = 1,180,670.41/1,223.40
6. Step 6: Final answer
   x = 965.07