Finding the Fourth Proportional to 2,578.13, 3,557.82 and 1,399.20

Step by Step Solution

1. Step 1: Write the proportion equation
   2,578.13 : 3,557.82 = 1,399.20 : x
2. Step 2: Convert to fraction form
   2,578.13/3,557.82 = 1,399.20/x
3. Step 3: Cross multiply
   2,578.13x = 3,557.82 × 1,399.20
4. Step 4: Simplify right side
   2,578.13x = 4,978,101.74
5. Step 5: Solve for x
   x = 4,978,101.74/2,578.13
6. Step 6: Final answer
   x = 1,930.90