Finding the Third Proportional to 10,424 and 21,128

Step by Step Solution

1. Step 1: Write the proportion equation
   10,424 : 21,128 = 21,128 : x
2. Step 2: Convert to fraction form
   10,424/21,128 = 21,128/x
3. Step 3: Cross multiply
   10,424x = 21,128 × 21,128
4. Step 4: Simplify right side
   10,424x = 446,392,384
5. Step 5: Solve for x
   x = 446,392,384/10,424
6. Step 6: Final answer
   x = 42,823.52