Finding the Fourth Proportional to 2,499.78, 3,745.57 and 855.43

Step by Step Solution

1. Step 1: Write the proportion equation
   2,499.78 : 3,745.57 = 855.43 : x
2. Step 2: Convert to fraction form
   2,499.78/3,745.57 = 855.43/x
3. Step 3: Cross multiply
   2,499.78x = 3,745.57 × 855.43
4. Step 4: Simplify right side
   2,499.78x = 3,204,072.95
5. Step 5: Solve for x
   x = 3,204,072.95/2,499.78
6. Step 6: Final answer
   x = 1,281.74