Finding the Fourth Proportional to 1,392.60, 1,922.40 and 868.56

Step by Step Solution

1. Step 1: Write the proportion equation
   1,392.60 : 1,922.40 = 868.56 : x
2. Step 2: Convert to fraction form
   1,392.60/1,922.40 = 868.56/x
3. Step 3: Cross multiply
   1,392.60x = 1,922.40 × 868.56
4. Step 4: Simplify right side
   1,392.60x = 1,669,719.74
5. Step 5: Solve for x
   x = 1,669,719.74/1,392.60
6. Step 6: Final answer
   x = 1,198.99