Finding the Fourth Proportional to 2,578.71, 3,558.63 and 1,399.79

Step by Step Solution

1. Step 1: Write the proportion equation
   2,578.71 : 3,558.63 = 1,399.79 : x
2. Step 2: Convert to fraction form
   2,578.71/3,558.63 = 1,399.79/x
3. Step 3: Cross multiply
   2,578.71x = 3,558.63 × 1,399.79
4. Step 4: Simplify right side
   2,578.71x = 4,981,334.69
5. Step 5: Solve for x
   x = 4,981,334.69/2,578.71
6. Step 6: Final answer
   x = 1,931.72