Finding the Third Proportional to 258.31 and 361.31

Step by Step Solution

1. Step 1: Write the proportion equation
   258.31 : 361.31 = 361.31 : x
2. Step 2: Convert to fraction form
   258.31/361.31 = 361.31/x
3. Step 3: Cross multiply
   258.31x = 361.31 × 361.31
4. Step 4: Simplify right side
   258.31x = 130,546.72
5. Step 5: Solve for x
   x = 130,546.72/258.31
6. Step 6: Final answer
   x = 505.38