Finding the Third Proportional to 639.56 and 936.56

Step by Step Solution

1. Step 1: Write the proportion equation
   639.56 : 936.56 = 936.56 : x
2. Step 2: Convert to fraction form
   639.56/936.56 = 936.56/x
3. Step 3: Cross multiply
   639.56x = 936.56 × 936.56
4. Step 4: Simplify right side
   639.56x = 877,149.32
5. Step 5: Solve for x
   x = 877,149.32/639.56
6. Step 6: Final answer
   x = 1,371.48