Finding the Fourth Proportional to 3,978.72, 5,958.36 and 3,434.40

Step by Step Solution

1. Step 1: Write the proportion equation
   3,978.72 : 5,958.36 = 3,434.40 : x
2. Step 2: Convert to fraction form
   3,978.72/5,958.36 = 3,434.40/x
3. Step 3: Cross multiply
   3,978.72x = 5,958.36 × 3,434.40
4. Step 4: Simplify right side
   3,978.72x = 20,463,391.58
5. Step 5: Solve for x
   x = 20,463,391.58/3,978.72
6. Step 6: Final answer
   x = 5,143.21