Finding the Fourth Proportional to 1,321.86, 1,983.33 and 456.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,321.86 : 1,983.33 = 456.78 : x
2. Step 2: Convert to fraction form
   1,321.86/1,983.33 = 456.78/x
3. Step 3: Cross multiply
   1,321.86x = 1,983.33 × 456.78
4. Step 4: Simplify right side
   1,321.86x = 905,945.48
5. Step 5: Solve for x
   x = 905,945.48/1,321.86
6. Step 6: Final answer
   x = 685.36