Finding the Third Proportional to 142.25 and 213.50

Step by Step Solution

1. Step 1: Write the proportion equation
   142.25 : 213.50 = 213.50 : x
2. Step 2: Convert to fraction form
   142.25/213.50 = 213.50/x
3. Step 3: Cross multiply
   142.25x = 213.50 × 213.50
4. Step 4: Simplify right side
   142.25x = 45,582.25
5. Step 5: Solve for x
   x = 45,582.25/142.25
6. Step 6: Final answer
   x = 320.44