Finding the Third Proportional to 9,639 and 12,960

Step by Step Solution

1. Step 1: Write the proportion equation
   9,639 : 12,960 = 12,960 : x
2. Step 2: Convert to fraction form
   9,639/12,960 = 12,960/x
3. Step 3: Cross multiply
   9,639x = 12,960 × 12,960
4. Step 4: Simplify right side
   9,639x = 167,961,600
5. Step 5: Solve for x
   x = 167,961,600/9,639
6. Step 6: Final answer
   x = 17,425.21