Finding the Fourth Proportional to 3,971.68, 5,480.12 and 2,399.86

Step by Step Solution

1. Step 1: Write the proportion equation
   3,971.68 : 5,480.12 = 2,399.86 : x
2. Step 2: Convert to fraction form
   3,971.68/5,480.12 = 2,399.86/x
3. Step 3: Cross multiply
   3,971.68x = 5,480.12 × 2,399.86
4. Step 4: Simplify right side
   3,971.68x = 13,151,520.78
5. Step 5: Solve for x
   x = 13,151,520.78/3,971.68
6. Step 6: Final answer
   x = 3,311.32