Finding the Fourth Proportional to 1,221.78, 1,685.01 and 868.82

Step by Step Solution

1. Step 1: Write the proportion equation
   1,221.78 : 1,685.01 = 868.82 : x
2. Step 2: Convert to fraction form
   1,221.78/1,685.01 = 868.82/x
3. Step 3: Cross multiply
   1,221.78x = 1,685.01 × 868.82
4. Step 4: Simplify right side
   1,221.78x = 1,463,970.39
5. Step 5: Solve for x
   x = 1,463,970.39/1,221.78
6. Step 6: Final answer
   x = 1,198.23