Finding the Third Proportional to 256,689 and 395,057.50

Step by Step Solution

1. Step 1: Write the proportion equation
   256,689 : 395,057.50 = 395,057.50 : x
2. Step 2: Convert to fraction form
   256,689/395,057.50 = 395,057.50/x
3. Step 3: Cross multiply
   256,689x = 395,057.50 × 395,057.50
4. Step 4: Simplify right side
   256,689x = 156,070,428,306.25
5. Step 5: Solve for x
   x = 156,070,428,306.25/256,689
6. Step 6: Final answer
   x = 608,013.70