Finding the Third Proportional to 640,972 and 978,408

Step by Step Solution

1. Step 1: Write the proportion equation
   640,972 : 978,408 = 978,408 : x
2. Step 2: Convert to fraction form
   640,972/978,408 = 978,408/x
3. Step 3: Cross multiply
   640,972x = 978,408 × 978,408
4. Step 4: Simplify right side
   640,972x = 957,282,214,464
5. Step 5: Solve for x
   x = 957,282,214,464/640,972
6. Step 6: Final answer
   x = 1,493,485.23