Finding the Fourth Proportional to 2,578.22, 3,557.94 and 1,399.30

Step by Step Solution

1. Step 1: Write the proportion equation
   2,578.22 : 3,557.94 = 1,399.30 : x
2. Step 2: Convert to fraction form
   2,578.22/3,557.94 = 1,399.30/x
3. Step 3: Cross multiply
   2,578.22x = 3,557.94 × 1,399.30
4. Step 4: Simplify right side
   2,578.22x = 4,978,616.55
5. Step 5: Solve for x
   x = 4,978,616.55/2,578.22
6. Step 6: Final answer
   x = 1,931.03