Finding the Third Proportional to 12,900 and 16,870

Step by Step Solution

1. Step 1: Write the proportion equation
   12,900 : 16,870 = 16,870 : x
2. Step 2: Convert to fraction form
   12,900/16,870 = 16,870/x
3. Step 3: Cross multiply
   12,900x = 16,870 × 16,870
4. Step 4: Simplify right side
   12,900x = 284,596,900
5. Step 5: Solve for x
   x = 284,596,900/12,900
6. Step 6: Final answer
   x = 22,061.78