Finding the Fourth Proportional to 2,171.29, 3,258.78 and 939.64

Step by Step Solution

1. Step 1: Write the proportion equation
   2,171.29 : 3,258.78 = 939.64 : x
2. Step 2: Convert to fraction form
   2,171.29/3,258.78 = 939.64/x
3. Step 3: Cross multiply
   2,171.29x = 3,258.78 × 939.64
4. Step 4: Simplify right side
   2,171.29x = 3,062,080.04
5. Step 5: Solve for x
   x = 3,062,080.04/2,171.29
6. Step 6: Final answer
   x = 1,410.26