Finding the Fourth Proportional to 3,919.76, 5,404.64 and 3,171.42

Step by Step Solution

1. Step 1: Write the proportion equation
   3,919.76 : 5,404.64 = 3,171.42 : x
2. Step 2: Convert to fraction form
   3,919.76/5,404.64 = 3,171.42/x
3. Step 3: Cross multiply
   3,919.76x = 5,404.64 × 3,171.42
4. Step 4: Simplify right side
   3,919.76x = 17,140,383.39
5. Step 5: Solve for x
   x = 17,140,383.39/3,919.76
6. Step 6: Final answer
   x = 4,372.81