Finding the Fourth Proportional to 3,918.78, 5,401.89 and 2,797.74

Step by Step Solution

1. Step 1: Write the proportion equation
   3,918.78 : 5,401.89 = 2,797.74 : x
2. Step 2: Convert to fraction form
   3,918.78/5,401.89 = 2,797.74/x
3. Step 3: Cross multiply
   3,918.78x = 5,401.89 × 2,797.74
4. Step 4: Simplify right side
   3,918.78x = 15,113,083.73
5. Step 5: Solve for x
   x = 15,113,083.73/3,918.78
6. Step 6: Final answer
   x = 3,856.58