Finding the Third Proportional to 12,728 and 21,148

Step by Step Solution

1. Step 1: Write the proportion equation
   12,728 : 21,148 = 21,148 : x
2. Step 2: Convert to fraction form
   12,728/21,148 = 21,148/x
3. Step 3: Cross multiply
   12,728x = 21,148 × 21,148
4. Step 4: Simplify right side
   12,728x = 447,237,904
5. Step 5: Solve for x
   x = 447,237,904/12,728
6. Step 6: Final answer
   x = 35,138.11