Finding the Third Proportional to 315,814 and 690,678

Step by Step Solution

1. Step 1: Write the proportion equation
   315,814 : 690,678 = 690,678 : x
2. Step 2: Convert to fraction form
   315,814/690,678 = 690,678/x
3. Step 3: Cross multiply
   315,814x = 690,678 × 690,678
4. Step 4: Simplify right side
   315,814x = 477,036,099,684
5. Step 5: Solve for x
   x = 477,036,099,684/315,814
6. Step 6: Final answer
   x = 1,510,497.00