Finding the Third Proportional to 309,926 and 678,819

Step by Step Solution

1. Step 1: Write the proportion equation
   309,926 : 678,819 = 678,819 : x
2. Step 2: Convert to fraction form
   309,926/678,819 = 678,819/x
3. Step 3: Cross multiply
   309,926x = 678,819 × 678,819
4. Step 4: Simplify right side
   309,926x = 460,795,234,761
5. Step 5: Solve for x
   x = 460,795,234,761/309,926
6. Step 6: Final answer
   x = 1,486,791.15