Finding the Third Proportional to 128.14 and 272.31

Step by Step Solution

1. Step 1: Write the proportion equation
   128.14 : 272.31 = 272.31 : x
2. Step 2: Convert to fraction form
   128.14/272.31 = 272.31/x
3. Step 3: Cross multiply
   128.14x = 272.31 × 272.31
4. Step 4: Simplify right side
   128.14x = 74,151.17
5. Step 5: Solve for x
   x = 74,151.17/128.14
6. Step 6: Final answer
   x = 578.65