Finding the Third Proportional to 640,980 and 978,420

Step by Step Solution

1. Step 1: Write the proportion equation
   640,980 : 978,420 = 978,420 : x
2. Step 2: Convert to fraction form
   640,980/978,420 = 978,420/x
3. Step 3: Cross multiply
   640,980x = 978,420 × 978,420
4. Step 4: Simplify right side
   640,980x = 957,305,696,400
5. Step 5: Solve for x
   x = 957,305,696,400/640,980
6. Step 6: Final answer
   x = 1,493,503.22