Finding the Fourth Proportional to 3,978.40, 5,490.18 and 2,406.04

Step by Step Solution

1. Step 1: Write the proportion equation
   3,978.40 : 5,490.18 = 2,406.04 : x
2. Step 2: Convert to fraction form
   3,978.40/5,490.18 = 2,406.04/x
3. Step 3: Cross multiply
   3,978.40x = 5,490.18 × 2,406.04
4. Step 4: Simplify right side
   3,978.40x = 13,209,592.69
5. Step 5: Solve for x
   x = 13,209,592.69/3,978.40
6. Step 6: Final answer
   x = 3,320.33