Finding the Fourth Proportional to 3,976.40, 5,960.94 and 2,128.78

Step by Step Solution

1. Step 1: Write the proportion equation
   3,976.40 : 5,960.94 = 2,128.78 : x
2. Step 2: Convert to fraction form
   3,976.40/5,960.94 = 2,128.78/x
3. Step 3: Cross multiply
   3,976.40x = 5,960.94 × 2,128.78
4. Step 4: Simplify right side
   3,976.40x = 12,689,529.85
5. Step 5: Solve for x
   x = 12,689,529.85/3,976.40
6. Step 6: Final answer
   x = 3,191.21