Finding the Fourth Proportional to 2,628.80, 3,938.16 and 2,540.88

Step by Step Solution

1. Step 1: Write the proportion equation
   2,628.80 : 3,938.16 = 2,540.88 : x
2. Step 2: Convert to fraction form
   2,628.80/3,938.16 = 2,540.88/x
3. Step 3: Cross multiply
   2,628.80x = 3,938.16 × 2,540.88
4. Step 4: Simplify right side
   2,628.80x = 10,006,391.98
5. Step 5: Solve for x
   x = 10,006,391.98/2,628.80
6. Step 6: Final answer
   x = 3,806.45