Finding the Third Proportional to 640,986 and 978,429

Step by Step Solution

1. Step 1: Write the proportion equation
   640,986 : 978,429 = 978,429 : x
2. Step 2: Convert to fraction form
   640,986/978,429 = 978,429/x
3. Step 3: Cross multiply
   640,986x = 978,429 × 978,429
4. Step 4: Simplify right side
   640,986x = 957,323,308,041
5. Step 5: Solve for x
   x = 957,323,308,041/640,986
6. Step 6: Final answer
   x = 1,493,516.72