Finding the Third Proportional to 269.88 and 408.56

Step by Step Solution

1. Step 1: Write the proportion equation
   269.88 : 408.56 = 408.56 : x
2. Step 2: Convert to fraction form
   269.88/408.56 = 408.56/x
3. Step 3: Cross multiply
   269.88x = 408.56 × 408.56
4. Step 4: Simplify right side
   269.88x = 166,923.32
5. Step 5: Solve for x
   x = 166,923.32/269.88
6. Step 6: Final answer
   x = 618.52