Finding the Third Proportional to 123.75 and 128.81

Step by Step Solution

1. Step 1: Write the proportion equation
   123.75 : 128.81 = 128.81 : x
2. Step 2: Convert to fraction form
   123.75/128.81 = 128.81/x
3. Step 3: Cross multiply
   123.75x = 128.81 × 128.81
4. Step 4: Simplify right side
   123.75x = 16,592.66
5. Step 5: Solve for x
   x = 16,592.66/123.75
6. Step 6: Final answer
   x = 134.08