Finding the Third Proportional to 300,870 and 640,728

Step by Step Solution

1. Step 1: Write the proportion equation
   300,870 : 640,728 = 640,728 : x
2. Step 2: Convert to fraction form
   300,870/640,728 = 640,728/x
3. Step 3: Cross multiply
   300,870x = 640,728 × 640,728
4. Step 4: Simplify right side
   300,870x = 410,532,369,984
5. Step 5: Solve for x
   x = 410,532,369,984/300,870
6. Step 6: Final answer
   x = 1,364,484.23