Finding the Third Proportional to 128.69 and 269.38

Step by Step Solution

1. Step 1: Write the proportion equation
   128.69 : 269.38 = 269.38 : x
2. Step 2: Convert to fraction form
   128.69/269.38 = 269.38/x
3. Step 3: Cross multiply
   128.69x = 269.38 × 269.38
4. Step 4: Simplify right side
   128.69x = 72,562.89
5. Step 5: Solve for x
   x = 72,562.89/128.69
6. Step 6: Final answer
   x = 563.87