Finding the Fourth Proportional to 2,617.76, 3,940.78 and 2,391.78

Step by Step Solution

1. Step 1: Write the proportion equation
   2,617.76 : 3,940.78 = 2,391.78 : x
2. Step 2: Convert to fraction form
   2,617.76/3,940.78 = 2,391.78/x
3. Step 3: Cross multiply
   2,617.76x = 3,940.78 × 2,391.78
4. Step 4: Simplify right side
   2,617.76x = 9,425,478.79
5. Step 5: Solve for x
   x = 9,425,478.79/2,617.76
6. Step 6: Final answer
   x = 3,600.59