Finding the Third Proportional to 640,927.69 and 978,340.78

Step by Step Solution

1. Step 1: Write the proportion equation
   640,927.69 : 978,340.78 = 978,340.78 : x
2. Step 2: Convert to fraction form
   640,927.69/978,340.78 = 978,340.78/x
3. Step 3: Cross multiply
   640,927.69x = 978,340.78 × 978,340.78
4. Step 4: Simplify right side
   640,927.69x = 957,150,684,256.86
5. Step 5: Solve for x
   x = 957,150,684,256.86/640,927.69
6. Step 6: Final answer
   x = 1,493,383.27