Finding the Third Proportional to 142.38 and 220.69

Step by Step Solution

1. Step 1: Write the proportion equation
   142.38 : 220.69 = 220.69 : x
2. Step 2: Convert to fraction form
   142.38/220.69 = 220.69/x
3. Step 3: Cross multiply
   142.38x = 220.69 × 220.69
4. Step 4: Simplify right side
   142.38x = 48,705.56
5. Step 5: Solve for x
   x = 48,705.56/142.38
6. Step 6: Final answer
   x = 342.07