Finding the Third Proportional to 142.38 and 321.79

Step by Step Solution

1. Step 1: Write the proportion equation
   142.38 : 321.79 = 321.79 : x
2. Step 2: Convert to fraction form
   142.38/321.79 = 321.79/x
3. Step 3: Cross multiply
   142.38x = 321.79 × 321.79
4. Step 4: Simplify right side
   142.38x = 103,545.69
5. Step 5: Solve for x
   x = 103,545.69/142.38
6. Step 6: Final answer
   x = 727.23