Finding the Fourth Proportional to 1,222.30, 1,686.72 and 691.27

Step by Step Solution

1. Step 1: Write the proportion equation
   1,222.30 : 1,686.72 = 691.27 : x
2. Step 2: Convert to fraction form
   1,222.30/1,686.72 = 691.27/x
3. Step 3: Cross multiply
   1,222.30x = 1,686.72 × 691.27
4. Step 4: Simplify right side
   1,222.30x = 1,165,978.93
5. Step 5: Solve for x
   x = 1,165,978.93/1,222.30
6. Step 6: Final answer
   x = 953.92