Finding the Third Proportional to 21,678 and 31,689

Step by Step Solution

1. Step 1: Write the proportion equation
   21,678 : 31,689 = 31,689 : x
2. Step 2: Convert to fraction form
   21,678/31,689 = 31,689/x
3. Step 3: Cross multiply
   21,678x = 31,689 × 31,689
4. Step 4: Simplify right side
   21,678x = 1,004,192,721
5. Step 5: Solve for x
   x = 1,004,192,721/21,678
6. Step 6: Final answer
   x = 46,323.13