Finding the Fourth Proportional to 2,557.78, 3,837.42 and 826.36

Step by Step Solution

1. Step 1: Write the proportion equation
   2,557.78 : 3,837.42 = 826.36 : x
2. Step 2: Convert to fraction form
   2,557.78/3,837.42 = 826.36/x
3. Step 3: Cross multiply
   2,557.78x = 3,837.42 × 826.36
4. Step 4: Simplify right side
   2,557.78x = 3,171,090.39
5. Step 5: Solve for x
   x = 3,171,090.39/2,557.78
6. Step 6: Final answer
   x = 1,239.78