Finding the Fourth Proportional to 3,978.34, 5,490 and 2,209.96

Step by Step Solution

1. Step 1: Write the proportion equation
   3,978.34 : 5,490 = 2,209.96 : x
2. Step 2: Convert to fraction form
   3,978.34/5,490 = 2,209.96/x
3. Step 3: Cross multiply
   3,978.34x = 5,490 × 2,209.96
4. Step 4: Simplify right side
   3,978.34x = 12,132,680.40
5. Step 5: Solve for x
   x = 12,132,680.40/3,978.34
6. Step 6: Final answer
   x = 3,049.68