Finding the Fourth Proportional to 1,222.89, 1,687.65 and 699.09

Step by Step Solution

1. Step 1: Write the proportion equation
   1,222.89 : 1,687.65 = 699.09 : x
2. Step 2: Convert to fraction form
   1,222.89/1,687.65 = 699.09/x
3. Step 3: Cross multiply
   1,222.89x = 1,687.65 × 699.09
4. Step 4: Simplify right side
   1,222.89x = 1,179,819.24
5. Step 5: Solve for x
   x = 1,179,819.24/1,222.89
6. Step 6: Final answer
   x = 964.78