Finding the Fourth Proportional to 1,222.98, 1,687.61 and 691.84

Step by Step Solution

1. Step 1: Write the proportion equation
   1,222.98 : 1,687.61 = 691.84 : x
2. Step 2: Convert to fraction form
   1,222.98/1,687.61 = 691.84/x
3. Step 3: Cross multiply
   1,222.98x = 1,687.61 × 691.84
4. Step 4: Simplify right side
   1,222.98x = 1,167,553.61
5. Step 5: Solve for x
   x = 1,167,553.61/1,222.98
6. Step 6: Final answer
   x = 954.68