Finding the Fourth Proportional to 3,939.75, 5,436.72 and 2,171.25

Step by Step Solution

1. Step 1: Write the proportion equation
   3,939.75 : 5,436.72 = 2,171.25 : x
2. Step 2: Convert to fraction form
   3,939.75/5,436.72 = 2,171.25/x
3. Step 3: Cross multiply
   3,939.75x = 5,436.72 × 2,171.25
4. Step 4: Simplify right side
   3,939.75x = 11,804,478.30
5. Step 5: Solve for x
   x = 11,804,478.30/3,939.75
6. Step 6: Final answer
   x = 2,996.25