Finding the Third Proportional to 258.38 and 364.31

Step by Step Solution

1. Step 1: Write the proportion equation
   258.38 : 364.31 = 364.31 : x
2. Step 2: Convert to fraction form
   258.38/364.31 = 364.31/x
3. Step 3: Cross multiply
   258.38x = 364.31 × 364.31
4. Step 4: Simplify right side
   258.38x = 132,723.60
5. Step 5: Solve for x
   x = 132,723.60/258.38
6. Step 6: Final answer
   x = 513.69