Finding the Third Proportional to 142.38 and 213.57

Step by Step Solution

1. Step 1: Write the proportion equation
   142.38 : 213.57 = 213.57 : x
2. Step 2: Convert to fraction form
   142.38/213.57 = 213.57/x
3. Step 3: Cross multiply
   142.38x = 213.57 × 213.57
4. Step 4: Simplify right side
   142.38x = 45,613.95
5. Step 5: Solve for x
   x = 45,613.95/142.38
6. Step 6: Final answer
   x = 320.36