Finding the Third Proportional to 9,872 and 21,688

Step by Step Solution

1. Step 1: Write the proportion equation
   9,872 : 21,688 = 21,688 : x
2. Step 2: Convert to fraction form
   9,872/21,688 = 21,688/x
3. Step 3: Cross multiply
   9,872x = 21,688 × 21,688
4. Step 4: Simplify right side
   9,872x = 470,369,344
5. Step 5: Solve for x
   x = 470,369,344/9,872
6. Step 6: Final answer
   x = 47,646.81