Finding the Third Proportional to 8,900 and 12,900

Step by Step Solution

1. Step 1: Write the proportion equation
   8,900 : 12,900 = 12,900 : x
2. Step 2: Convert to fraction form
   8,900/12,900 = 12,900/x
3. Step 3: Cross multiply
   8,900x = 12,900 × 12,900
4. Step 4: Simplify right side
   8,900x = 166,410,000
5. Step 5: Solve for x
   x = 166,410,000/8,900
6. Step 6: Final answer
   x = 18,697.75