Finding the Fourth Proportional to 2,581.12, 3,872.52 and 826.40

Step by Step Solution

1. Step 1: Write the proportion equation
   2,581.12 : 3,872.52 = 826.40 : x
2. Step 2: Convert to fraction form
   2,581.12/3,872.52 = 826.40/x
3. Step 3: Cross multiply
   2,581.12x = 3,872.52 × 826.40
4. Step 4: Simplify right side
   2,581.12x = 3,200,250.53
5. Step 5: Solve for x
   x = 3,200,250.53/2,581.12
6. Step 6: Final answer
   x = 1,239.87