Finding the Third Proportional to 321,664 and 686,076

Step by Step Solution

1. Step 1: Write the proportion equation
   321,664 : 686,076 = 686,076 : x
2. Step 2: Convert to fraction form
   321,664/686,076 = 686,076/x
3. Step 3: Cross multiply
   321,664x = 686,076 × 686,076
4. Step 4: Simplify right side
   321,664x = 470,700,277,776
5. Step 5: Solve for x
   x = 470,700,277,776/321,664
6. Step 6: Final answer
   x = 1,463,329.06