Finding the Third Proportional to 639.38 and 993.38

Step by Step Solution

1. Step 1: Write the proportion equation
   639.38 : 993.38 = 993.38 : x
2. Step 2: Convert to fraction form
   639.38/993.38 = 993.38/x
3. Step 3: Cross multiply
   639.38x = 993.38 × 993.38
4. Step 4: Simplify right side
   639.38x = 986,793.89
5. Step 5: Solve for x
   x = 986,793.89/639.38
6. Step 6: Final answer
   x = 1,543.37