Finding the Third Proportional to 10,686 and 14,139

Step by Step Solution

1. Step 1: Write the proportion equation
   10,686 : 14,139 = 14,139 : x
2. Step 2: Convert to fraction form
   10,686/14,139 = 14,139/x
3. Step 3: Cross multiply
   10,686x = 14,139 × 14,139
4. Step 4: Simplify right side
   10,686x = 199,911,321
5. Step 5: Solve for x
   x = 199,911,321/10,686
6. Step 6: Final answer
   x = 18,707.78