Finding the Fourth Proportional to 2,578.77, 3,558.74 and 1,399.86

Step by Step Solution

1. Step 1: Write the proportion equation
   2,578.77 : 3,558.74 = 1,399.86 : x
2. Step 2: Convert to fraction form
   2,578.77/3,558.74 = 1,399.86/x
3. Step 3: Cross multiply
   2,578.77x = 3,558.74 × 1,399.86
4. Step 4: Simplify right side
   2,578.77x = 4,981,730.78
5. Step 5: Solve for x
   x = 4,981,730.78/2,578.77
6. Step 6: Final answer
   x = 1,931.82