Finding the Third Proportional to 10,128 and 20,661

Step by Step Solution

1. Step 1: Write the proportion equation
   10,128 : 20,661 = 20,661 : x
2. Step 2: Convert to fraction form
   10,128/20,661 = 20,661/x
3. Step 3: Cross multiply
   10,128x = 20,661 × 20,661
4. Step 4: Simplify right side
   10,128x = 426,876,921
5. Step 5: Solve for x
   x = 426,876,921/10,128
6. Step 6: Final answer
   x = 42,148.20