Finding the Third Proportional to 257,909 and 394,495.50

Step by Step Solution

1. Step 1: Write the proportion equation
   257,909 : 394,495.50 = 394,495.50 : x
2. Step 2: Convert to fraction form
   257,909/394,495.50 = 394,495.50/x
3. Step 3: Cross multiply
   257,909x = 394,495.50 × 394,495.50
4. Step 4: Simplify right side
   257,909x = 155,626,699,520.25
5. Step 5: Solve for x
   x = 155,626,699,520.25/257,909
6. Step 6: Final answer
   x = 603,417.09