Finding the Fourth Proportional to 3,978.10, 5,489.69 and 2,209.67

Step by Step Solution

1. Step 1: Write the proportion equation
   3,978.10 : 5,489.69 = 2,209.67 : x
2. Step 2: Convert to fraction form
   3,978.10/5,489.69 = 2,209.67/x
3. Step 3: Cross multiply
   3,978.10x = 5,489.69 × 2,209.67
4. Step 4: Simplify right side
   3,978.10x = 12,130,403.30
5. Step 5: Solve for x
   x = 12,130,403.30/3,978.10
6. Step 6: Final answer
   x = 3,049.30