Finding the Fourth Proportional to 3,978.38, 5,490.19 and 2,487.17

Step by Step Solution

1. Step 1: Write the proportion equation
   3,978.38 : 5,490.19 = 2,487.17 : x
2. Step 2: Convert to fraction form
   3,978.38/5,490.19 = 2,487.17/x
3. Step 3: Cross multiply
   3,978.38x = 5,490.19 × 2,487.17
4. Step 4: Simplify right side
   3,978.38x = 13,655,023.43
5. Step 5: Solve for x
   x = 13,655,023.43/3,978.38
6. Step 6: Final answer
   x = 3,432.31