Finding the Fourth Proportional to 2,600.28, 3,900.78 and 868.50

Step by Step Solution

1. Step 1: Write the proportion equation
   2,600.28 : 3,900.78 = 868.50 : x
2. Step 2: Convert to fraction form
   2,600.28/3,900.78 = 868.50/x
3. Step 3: Cross multiply
   2,600.28x = 3,900.78 × 868.50
4. Step 4: Simplify right side
   2,600.28x = 3,387,827.43
5. Step 5: Solve for x
   x = 3,387,827.43/2,600.28
6. Step 6: Final answer
   x = 1,302.87