Finding the Third Proportional to 12,688 and 19,723

Step by Step Solution

1. Step 1: Write the proportion equation
   12,688 : 19,723 = 19,723 : x
2. Step 2: Convert to fraction form
   12,688/19,723 = 19,723/x
3. Step 3: Cross multiply
   12,688x = 19,723 × 19,723
4. Step 4: Simplify right side
   12,688x = 388,996,729
5. Step 5: Solve for x
   x = 388,996,729/12,688
6. Step 6: Final answer
   x = 30,658.63