Finding the Fourth Proportional to 4,085.09, 5,640.60 and 3,139.38

Step by Step Solution

1. Step 1: Write the proportion equation
   4,085.09 : 5,640.60 = 3,139.38 : x
2. Step 2: Convert to fraction form
   4,085.09/5,640.60 = 3,139.38/x
3. Step 3: Cross multiply
   4,085.09x = 5,640.60 × 3,139.38
4. Step 4: Simplify right side
   4,085.09x = 17,707,986.83
5. Step 5: Solve for x
   x = 17,707,986.83/4,085.09
6. Step 6: Final answer
   x = 4,334.78