Finding the Third Proportional to 639 and 1,019.25

Step by Step Solution

1. Step 1: Write the proportion equation
   639 : 1,019.25 = 1,019.25 : x
2. Step 2: Convert to fraction form
   639/1,019.25 = 1,019.25/x
3. Step 3: Cross multiply
   639x = 1,019.25 × 1,019.25
4. Step 4: Simplify right side
   639x = 1,038,870.56
5. Step 5: Solve for x
   x = 1,038,870.56/639
6. Step 6: Final answer
   x = 1,625.78