Finding the Third Proportional to 129.75 and 142.50

Step by Step Solution

1. Step 1: Write the proportion equation
   129.75 : 142.50 = 142.50 : x
2. Step 2: Convert to fraction form
   129.75/142.50 = 142.50/x
3. Step 3: Cross multiply
   129.75x = 142.50 × 142.50
4. Step 4: Simplify right side
   129.75x = 20,306.25
5. Step 5: Solve for x
   x = 20,306.25/129.75
6. Step 6: Final answer
   x = 156.50