Finding the Fourth Proportional to 2,578.23, 3,557.96 and 1,399.31

Step by Step Solution

1. Step 1: Write the proportion equation
   2,578.23 : 3,557.96 = 1,399.31 : x
2. Step 2: Convert to fraction form
   2,578.23/3,557.96 = 1,399.31/x
3. Step 3: Cross multiply
   2,578.23x = 3,557.96 × 1,399.31
4. Step 4: Simplify right side
   2,578.23x = 4,978,674.72
5. Step 5: Solve for x
   x = 4,978,674.72/2,578.23
6. Step 6: Final answer
   x = 1,931.04