Finding the Third Proportional to 644.25 and 814.50

Step by Step Solution

1. Step 1: Write the proportion equation
   644.25 : 814.50 = 814.50 : x
2. Step 2: Convert to fraction form
   644.25/814.50 = 814.50/x
3. Step 3: Cross multiply
   644.25x = 814.50 × 814.50
4. Step 4: Simplify right side
   644.25x = 663,410.25
5. Step 5: Solve for x
   x = 663,410.25/644.25
6. Step 6: Final answer
   x = 1,029.74