Finding the Fourth Proportional to 1,428.27, 1,971.15 and 868.61

Step by Step Solution

1. Step 1: Write the proportion equation
   1,428.27 : 1,971.15 = 868.61 : x
2. Step 2: Convert to fraction form
   1,428.27/1,971.15 = 868.61/x
3. Step 3: Cross multiply
   1,428.27x = 1,971.15 × 868.61
4. Step 4: Simplify right side
   1,428.27x = 1,712,160.60
5. Step 5: Solve for x
   x = 1,712,160.60/1,428.27
6. Step 6: Final answer
   x = 1,198.77