Finding the Fourth Proportional to 1,221.59, 1,831.83 and 388.41

Step by Step Solution

1. Step 1: Write the proportion equation
   1,221.59 : 1,831.83 = 388.41 : x
2. Step 2: Convert to fraction form
   1,221.59/1,831.83 = 388.41/x
3. Step 3: Cross multiply
   1,221.59x = 1,831.83 × 388.41
4. Step 4: Simplify right side
   1,221.59x = 711,499.15
5. Step 5: Solve for x
   x = 711,499.15/1,221.59
6. Step 6: Final answer
   x = 582.44