Finding the Third Proportional to 257,166 and 399,763.50

Step by Step Solution

1. Step 1: Write the proportion equation
   257,166 : 399,763.50 = 399,763.50 : x
2. Step 2: Convert to fraction form
   257,166/399,763.50 = 399,763.50/x
3. Step 3: Cross multiply
   257,166x = 399,763.50 × 399,763.50
4. Step 4: Simplify right side
   257,166x = 159,810,855,932.25
5. Step 5: Solve for x
   x = 159,810,855,932.25/257,166
6. Step 6: Final answer
   x = 621,430.73