Finding the Fourth Proportional to 2,171.43, 3,258.96 and 939.78

Step by Step Solution

1. Step 1: Write the proportion equation
   2,171.43 : 3,258.96 = 939.78 : x
2. Step 2: Convert to fraction form
   2,171.43/3,258.96 = 939.78/x
3. Step 3: Cross multiply
   2,171.43x = 3,258.96 × 939.78
4. Step 4: Simplify right side
   2,171.43x = 3,062,705.43
5. Step 5: Solve for x
   x = 3,062,705.43/2,171.43
6. Step 6: Final answer
   x = 1,410.46