Finding the Fourth Proportional to 2,578.31, 3,865.58 and 822.31

Step by Step Solution

1. Step 1: Write the proportion equation
   2,578.31 : 3,865.58 = 822.31 : x
2. Step 2: Convert to fraction form
   2,578.31/3,865.58 = 822.31/x
3. Step 3: Cross multiply
   2,578.31x = 3,865.58 × 822.31
4. Step 4: Simplify right side
   2,578.31x = 3,178,694.40
5. Step 5: Solve for x
   x = 3,178,694.40/2,578.31
6. Step 6: Final answer
   x = 1,232.86