Finding the Fourth Proportional to 3,919.38, 5,406.82 and 2,855.49

Step by Step Solution

1. Step 1: Write the proportion equation
   3,919.38 : 5,406.82 = 2,855.49 : x
2. Step 2: Convert to fraction form
   3,919.38/5,406.82 = 2,855.49/x
3. Step 3: Cross multiply
   3,919.38x = 5,406.82 × 2,855.49
4. Step 4: Simplify right side
   3,919.38x = 15,439,113.30
5. Step 5: Solve for x
   x = 15,439,113.30/3,919.38
6. Step 6: Final answer
   x = 3,939.17