Finding the Fourth Proportional to 1,200.80, 1,656.60 and 868.50

Step by Step Solution

1. Step 1: Write the proportion equation
   1,200.80 : 1,656.60 = 868.50 : x
2. Step 2: Convert to fraction form
   1,200.80/1,656.60 = 868.50/x
3. Step 3: Cross multiply
   1,200.80x = 1,656.60 × 868.50
4. Step 4: Simplify right side
   1,200.80x = 1,438,757.10
5. Step 5: Solve for x
   x = 1,438,757.10/1,200.80
6. Step 6: Final answer
   x = 1,198.17