Finding the Fourth Proportional to 1,222.80, 1,687.49 and 698.73

Step by Step Solution

1. Step 1: Write the proportion equation
   1,222.80 : 1,687.49 = 698.73 : x
2. Step 2: Convert to fraction form
   1,222.80/1,687.49 = 698.73/x
3. Step 3: Cross multiply
   1,222.80x = 1,687.49 × 698.73
4. Step 4: Simplify right side
   1,222.80x = 1,179,096.39
5. Step 5: Solve for x
   x = 1,179,096.39/1,222.80
6. Step 6: Final answer
   x = 964.26