Finding the Third Proportional to 639.94 and 1,020.28

Step by Step Solution

1. Step 1: Write the proportion equation
   639.94 : 1,020.28 = 1,020.28 : x
2. Step 2: Convert to fraction form
   639.94/1,020.28 = 1,020.28/x
3. Step 3: Cross multiply
   639.94x = 1,020.28 × 1,020.28
4. Step 4: Simplify right side
   639.94x = 1,040,973.83
5. Step 5: Solve for x
   x = 1,040,973.83/639.94
6. Step 6: Final answer
   x = 1,626.68