Finding the Third Proportional to 257.34 and 399.52

Step by Step Solution

1. Step 1: Write the proportion equation
   257.34 : 399.52 = 399.52 : x
2. Step 2: Convert to fraction form
   257.34/399.52 = 399.52/x
3. Step 3: Cross multiply
   257.34x = 399.52 × 399.52
4. Step 4: Simplify right side
   257.34x = 159,612.73
5. Step 5: Solve for x
   x = 159,612.73/257.34
6. Step 6: Final answer
   x = 620.23