Finding the Third Proportional to 258,711 and 386,470.50

Step by Step Solution

1. Step 1: Write the proportion equation
   258,711 : 386,470.50 = 386,470.50 : x
2. Step 2: Convert to fraction form
   258,711/386,470.50 = 386,470.50/x
3. Step 3: Cross multiply
   258,711x = 386,470.50 × 386,470.50
4. Step 4: Simplify right side
   258,711x = 149,359,447,370.25
5. Step 5: Solve for x
   x = 149,359,447,370.25/258,711
6. Step 6: Final answer
   x = 577,321.60