Finding the Third Proportional to 640,940 and 978,359

Step by Step Solution

1. Step 1: Write the proportion equation
   640,940 : 978,359 = 978,359 : x
2. Step 2: Convert to fraction form
   640,940/978,359 = 978,359/x
3. Step 3: Cross multiply
   640,940x = 978,359 × 978,359
4. Step 4: Simplify right side
   640,940x = 957,186,332,881
5. Step 5: Solve for x
   x = 957,186,332,881/640,940
6. Step 6: Final answer
   x = 1,493,410.20