Finding the Third Proportional to 258,489 and 386,185.50

Step by Step Solution

1. Step 1: Write the proportion equation
   258,489 : 386,185.50 = 386,185.50 : x
2. Step 2: Convert to fraction form
   258,489/386,185.50 = 386,185.50/x
3. Step 3: Cross multiply
   258,489x = 386,185.50 × 386,185.50
4. Step 4: Simplify right side
   258,489x = 149,139,240,410.25
5. Step 5: Solve for x
   x = 149,139,240,410.25/258,489
6. Step 6: Final answer
   x = 576,965.52