Finding the Third Proportional to 128.25 and 133.50

Step by Step Solution

1. Step 1: Write the proportion equation
   128.25 : 133.50 = 133.50 : x
2. Step 2: Convert to fraction form
   128.25/133.50 = 133.50/x
3. Step 3: Cross multiply
   128.25x = 133.50 × 133.50
4. Step 4: Simplify right side
   128.25x = 17,822.25
5. Step 5: Solve for x
   x = 17,822.25/128.25
6. Step 6: Final answer
   x = 138.96