Finding the Third Proportional to 686.50 and 806.50

Step by Step Solution

1. Step 1: Write the proportion equation
   686.50 : 806.50 = 806.50 : x
2. Step 2: Convert to fraction form
   686.50/806.50 = 806.50/x
3. Step 3: Cross multiply
   686.50x = 806.50 × 806.50
4. Step 4: Simplify right side
   686.50x = 650,442.25
5. Step 5: Solve for x
   x = 650,442.25/686.50
6. Step 6: Final answer
   x = 947.48