Finding the Fourth Proportional to 2,578.47, 3,558.29 and 1,399.56

Step by Step Solution

1. Step 1: Write the proportion equation
   2,578.47 : 3,558.29 = 1,399.56 : x
2. Step 2: Convert to fraction form
   2,578.47/3,558.29 = 1,399.56/x
3. Step 3: Cross multiply
   2,578.47x = 3,558.29 × 1,399.56
4. Step 4: Simplify right side
   2,578.47x = 4,980,040.35
5. Step 5: Solve for x
   x = 4,980,040.35/2,578.47
6. Step 6: Final answer
   x = 1,931.39