Finding the Third Proportional to 640.50 and 694.50

Step by Step Solution

1. Step 1: Write the proportion equation
   640.50 : 694.50 = 694.50 : x
2. Step 2: Convert to fraction form
   640.50/694.50 = 694.50/x
3. Step 3: Cross multiply
   640.50x = 694.50 × 694.50
4. Step 4: Simplify right side
   640.50x = 482,330.25
5. Step 5: Solve for x
   x = 482,330.25/640.50
6. Step 6: Final answer
   x = 753.05