Finding the Third Proportional to 313,870 and 687,064

Step by Step Solution

1. Step 1: Write the proportion equation
   313,870 : 687,064 = 687,064 : x
2. Step 2: Convert to fraction form
   313,870/687,064 = 687,064/x
3. Step 3: Cross multiply
   313,870x = 687,064 × 687,064
4. Step 4: Simplify right side
   313,870x = 472,056,940,096
5. Step 5: Solve for x
   x = 472,056,940,096/313,870
6. Step 6: Final answer
   x = 1,503,988.72