Finding the Third Proportional to 142.88 and 214.88

Step by Step Solution

1. Step 1: Write the proportion equation
   142.88 : 214.88 = 214.88 : x
2. Step 2: Convert to fraction form
   142.88/214.88 = 214.88/x
3. Step 3: Cross multiply
   142.88x = 214.88 × 214.88
4. Step 4: Simplify right side
   142.88x = 46,171.27
5. Step 5: Solve for x
   x = 46,171.27/142.88
6. Step 6: Final answer
   x = 323.16