Finding the Third Proportional to 128.31 and 273.69

Step by Step Solution

1. Step 1: Write the proportion equation
   128.31 : 273.69 = 273.69 : x
2. Step 2: Convert to fraction form
   128.31/273.69 = 273.69/x
3. Step 3: Cross multiply
   128.31x = 273.69 × 273.69
4. Step 4: Simplify right side
   128.31x = 74,904.85
5. Step 5: Solve for x
   x = 74,904.85/128.31
6. Step 6: Final answer
   x = 583.77