Finding the Fourth Proportional to 2,858.43, 4,287.59 and 778.40

Step by Step Solution

1. Step 1: Write the proportion equation
   2,858.43 : 4,287.59 = 778.40 : x
2. Step 2: Convert to fraction form
   2,858.43/4,287.59 = 778.40/x
3. Step 3: Cross multiply
   2,858.43x = 4,287.59 × 778.40
4. Step 4: Simplify right side
   2,858.43x = 3,337,472.72
5. Step 5: Solve for x
   x = 3,337,472.72/2,858.43
6. Step 6: Final answer
   x = 1,167.59