Finding the Fourth Proportional to 3,913.88, 5,401.15 and 2,145.55

Step by Step Solution

1. Step 1: Write the proportion equation
   3,913.88 : 5,401.15 = 2,145.55 : x
2. Step 2: Convert to fraction form
   3,913.88/5,401.15 = 2,145.55/x
3. Step 3: Cross multiply
   3,913.88x = 5,401.15 × 2,145.55
4. Step 4: Simplify right side
   3,913.88x = 11,588,418.52
5. Step 5: Solve for x
   x = 11,588,418.52/3,913.88
6. Step 6: Final answer
   x = 2,960.86