Finding the Third Proportional to 9,871 and 21,145

Step by Step Solution

1. Step 1: Write the proportion equation
   9,871 : 21,145 = 21,145 : x
2. Step 2: Convert to fraction form
   9,871/21,145 = 21,145/x
3. Step 3: Cross multiply
   9,871x = 21,145 × 21,145
4. Step 4: Simplify right side
   9,871x = 447,111,025
5. Step 5: Solve for x
   x = 447,111,025/9,871
6. Step 6: Final answer
   x = 45,295.41