Finding the Fourth Proportional to 3,978.88, 5,490.24 and 2,738.56

Step by Step Solution

1. Step 1: Write the proportion equation
   3,978.88 : 5,490.24 = 2,738.56 : x
2. Step 2: Convert to fraction form
   3,978.88/5,490.24 = 2,738.56/x
3. Step 3: Cross multiply
   3,978.88x = 5,490.24 × 2,738.56
4. Step 4: Simplify right side
   3,978.88x = 15,035,351.65
5. Step 5: Solve for x
   x = 15,035,351.65/3,978.88
6. Step 6: Final answer
   x = 3,778.79