Finding the Third Proportional to 408.56 and 621.38

Step by Step Solution

1. Step 1: Write the proportion equation
   408.56 : 621.38 = 621.38 : x
2. Step 2: Convert to fraction form
   408.56/621.38 = 621.38/x
3. Step 3: Cross multiply
   408.56x = 621.38 × 621.38
4. Step 4: Simplify right side
   408.56x = 386,106.89
5. Step 5: Solve for x
   x = 386,106.89/408.56
6. Step 6: Final answer
   x = 945.04