Finding the Third Proportional to 13,688 and 21,455

Step by Step Solution

1. Step 1: Write the proportion equation
   13,688 : 21,455 = 21,455 : x
2. Step 2: Convert to fraction form
   13,688/21,455 = 21,455/x
3. Step 3: Cross multiply
   13,688x = 21,455 × 21,455
4. Step 4: Simplify right side
   13,688x = 460,317,025
5. Step 5: Solve for x
   x = 460,317,025/13,688
6. Step 6: Final answer
   x = 33,629.24