Finding the Fourth Proportional to 3,978.30, 5,488.98 and 2,487.78

Step by Step Solution

1. Step 1: Write the proportion equation
   3,978.30 : 5,488.98 = 2,487.78 : x
2. Step 2: Convert to fraction form
   3,978.30/5,488.98 = 2,487.78/x
3. Step 3: Cross multiply
   3,978.30x = 5,488.98 × 2,487.78
4. Step 4: Simplify right side
   3,978.30x = 13,655,374.66
5. Step 5: Solve for x
   x = 13,655,374.66/3,978.30
6. Step 6: Final answer
   x = 3,432.46