Finding the Third Proportional to 685.50 and 763.50

Step by Step Solution

1. Step 1: Write the proportion equation
   685.50 : 763.50 = 763.50 : x
2. Step 2: Convert to fraction form
   685.50/763.50 = 763.50/x
3. Step 3: Cross multiply
   685.50x = 763.50 × 763.50
4. Step 4: Simplify right side
   685.50x = 582,932.25
5. Step 5: Solve for x
   x = 582,932.25/685.50
6. Step 6: Final answer
   x = 850.38