Finding the Fourth Proportional to 1,222.72, 1,687.32 and 691.63

Step by Step Solution

1. Step 1: Write the proportion equation
   1,222.72 : 1,687.32 = 691.63 : x
2. Step 2: Convert to fraction form
   1,222.72/1,687.32 = 691.63/x
3. Step 3: Cross multiply
   1,222.72x = 1,687.32 × 691.63
4. Step 4: Simplify right side
   1,222.72x = 1,166,996.91
5. Step 5: Solve for x
   x = 1,166,996.91/1,222.72
6. Step 6: Final answer
   x = 954.43