Finding the Fourth Proportional to 2,581.42, 3,871.81 and 826.61

Step by Step Solution

1. Step 1: Write the proportion equation
   2,581.42 : 3,871.81 = 826.61 : x
2. Step 2: Convert to fraction form
   2,581.42/3,871.81 = 826.61/x
3. Step 3: Cross multiply
   2,581.42x = 3,871.81 × 826.61
4. Step 4: Simplify right side
   2,581.42x = 3,200,476.86
5. Step 5: Solve for x
   x = 3,200,476.86/2,581.42
6. Step 6: Final answer
   x = 1,239.81