Finding the Fourth Proportional to 3,978.15, 5,490.03 and 2,209.65

Step by Step Solution

1. Step 1: Write the proportion equation
   3,978.15 : 5,490.03 = 2,209.65 : x
2. Step 2: Convert to fraction form
   3,978.15/5,490.03 = 2,209.65/x
3. Step 3: Cross multiply
   3,978.15x = 5,490.03 × 2,209.65
4. Step 4: Simplify right side
   3,978.15x = 12,131,044.79
5. Step 5: Solve for x
   x = 12,131,044.79/3,978.15
6. Step 6: Final answer
   x = 3,049.42