Finding the Fourth Proportional to 1,338.72, 2,007.84 and 688.96

Step by Step Solution

1. Step 1: Write the proportion equation
   1,338.72 : 2,007.84 = 688.96 : x
2. Step 2: Convert to fraction form
   1,338.72/2,007.84 = 688.96/x
3. Step 3: Cross multiply
   1,338.72x = 2,007.84 × 688.96
4. Step 4: Simplify right side
   1,338.72x = 1,383,321.45
5. Step 5: Solve for x
   x = 1,383,321.45/1,338.72
6. Step 6: Final answer
   x = 1,033.32