Finding the Fourth Proportional to 2,139.52, 3,205.63 and 1,728.85

Step by Step Solution

1. Step 1: Write the proportion equation
   2,139.52 : 3,205.63 = 1,728.85 : x
2. Step 2: Convert to fraction form
   2,139.52/3,205.63 = 1,728.85/x
3. Step 3: Cross multiply
   2,139.52x = 3,205.63 × 1,728.85
4. Step 4: Simplify right side
   2,139.52x = 5,542,028.75
5. Step 5: Solve for x
   x = 5,542,028.75/2,139.52
6. Step 6: Final answer
   x = 2,590.32