Finding the Third Proportional to 256.50 and 402.38

Step by Step Solution

1. Step 1: Write the proportion equation
   256.50 : 402.38 = 402.38 : x
2. Step 2: Convert to fraction form
   256.50/402.38 = 402.38/x
3. Step 3: Cross multiply
   256.50x = 402.38 × 402.38
4. Step 4: Simplify right side
   256.50x = 161,905.64
5. Step 5: Solve for x
   x = 161,905.64/256.50
6. Step 6: Final answer
   x = 631.21