Finding the Third Proportional to 11,520 and 12,720

Step by Step Solution

1. Step 1: Write the proportion equation
   11,520 : 12,720 = 12,720 : x
2. Step 2: Convert to fraction form
   11,520/12,720 = 12,720/x
3. Step 3: Cross multiply
   11,520x = 12,720 × 12,720
4. Step 4: Simplify right side
   11,520x = 161,798,400
5. Step 5: Solve for x
   x = 161,798,400/11,520
6. Step 6: Final answer
   x = 14,045