Finding the Third Proportional to 258,665.50 and 399,073

Step by Step Solution

1. Step 1: Write the proportion equation
   258,665.50 : 399,073 = 399,073 : x
2. Step 2: Convert to fraction form
   258,665.50/399,073 = 399,073/x
3. Step 3: Cross multiply
   258,665.50x = 399,073 × 399,073
4. Step 4: Simplify right side
   258,665.50x = 159,259,259,329
5. Step 5: Solve for x
   x = 159,259,259,329/258,665.50
6. Step 6: Final answer
   x = 615,695.79