Finding the Third Proportional to 610.50 and 649.50

Step by Step Solution

1. Step 1: Write the proportion equation
   610.50 : 649.50 = 649.50 : x
2. Step 2: Convert to fraction form
   610.50/649.50 = 649.50/x
3. Step 3: Cross multiply
   610.50x = 649.50 × 649.50
4. Step 4: Simplify right side
   610.50x = 421,850.25
5. Step 5: Solve for x
   x = 421,850.25/610.50
6. Step 6: Final answer
   x = 690.99