Finding the Third Proportional to 677,487 and 990,789

Step by Step Solution

1. Step 1: Write the proportion equation
   677,487 : 990,789 = 990,789 : x
2. Step 2: Convert to fraction form
   677,487/990,789 = 990,789/x
3. Step 3: Cross multiply
   677,487x = 990,789 × 990,789
4. Step 4: Simplify right side
   677,487x = 981,662,842,521
5. Step 5: Solve for x
   x = 981,662,842,521/677,487
6. Step 6: Final answer
   x = 1,448,976.65