Finding the Fourth Proportional to 3,078.42, 4,238.37 and 2,490.90

Step by Step Solution

1. Step 1: Write the proportion equation
   3,078.42 : 4,238.37 = 2,490.90 : x
2. Step 2: Convert to fraction form
   3,078.42/4,238.37 = 2,490.90/x
3. Step 3: Cross multiply
   3,078.42x = 4,238.37 × 2,490.90
4. Step 4: Simplify right side
   3,078.42x = 10,557,355.83
5. Step 5: Solve for x
   x = 10,557,355.83/3,078.42
6. Step 6: Final answer
   x = 3,429.47