Finding the Fourth Proportional to 1,320.78, 1,822.61 and 731.21

Step by Step Solution

1. Step 1: Write the proportion equation
   1,320.78 : 1,822.61 = 731.21 : x
2. Step 2: Convert to fraction form
   1,320.78/1,822.61 = 731.21/x
3. Step 3: Cross multiply
   1,320.78x = 1,822.61 × 731.21
4. Step 4: Simplify right side
   1,320.78x = 1,332,697.89
5. Step 5: Solve for x
   x = 1,332,697.89/1,320.78
6. Step 6: Final answer
   x = 1,009.02