Finding the Fourth Proportional to 2,581.31, 3,872.55 and 826.43

Step by Step Solution

1. Step 1: Write the proportion equation
   2,581.31 : 3,872.55 = 826.43 : x
2. Step 2: Convert to fraction form
   2,581.31/3,872.55 = 826.43/x
3. Step 3: Cross multiply
   2,581.31x = 3,872.55 × 826.43
4. Step 4: Simplify right side
   2,581.31x = 3,200,380.31
5. Step 5: Solve for x
   x = 3,200,380.31/2,581.31
6. Step 6: Final answer
   x = 1,239.83