Finding the Third Proportional to 424.69 and 640.27

Step by Step Solution

1. Step 1: Write the proportion equation
   424.69 : 640.27 = 640.27 : x
2. Step 2: Convert to fraction form
   424.69/640.27 = 640.27/x
3. Step 3: Cross multiply
   424.69x = 640.27 × 640.27
4. Step 4: Simplify right side
   424.69x = 409,940.07
5. Step 5: Solve for x
   x = 409,940.07/424.69
6. Step 6: Final answer
   x = 965.27