Finding the Third Proportional to 356,840 and 489,310.50

Step by Step Solution

1. Step 1: Write the proportion equation
   356,840 : 489,310.50 = 489,310.50 : x
2. Step 2: Convert to fraction form
   356,840/489,310.50 = 489,310.50/x
3. Step 3: Cross multiply
   356,840x = 489,310.50 × 489,310.50
4. Step 4: Simplify right side
   356,840x = 239,424,765,410.25
5. Step 5: Solve for x
   x = 239,424,765,410.25/356,840
6. Step 6: Final answer
   x = 670,958.32