Finding the Third Proportional to 128.25 and 178.31

Step by Step Solution

1. Step 1: Write the proportion equation
   128.25 : 178.31 = 178.31 : x
2. Step 2: Convert to fraction form
   128.25/178.31 = 178.31/x
3. Step 3: Cross multiply
   128.25x = 178.31 × 178.31
4. Step 4: Simplify right side
   128.25x = 31,795.35
5. Step 5: Solve for x
   x = 31,795.35/128.25
6. Step 6: Final answer
   x = 247.92