Finding the Third Proportional to 7,876 and 12,690

Step by Step Solution

1. Step 1: Write the proportion equation
   7,876 : 12,690 = 12,690 : x
2. Step 2: Convert to fraction form
   7,876/12,690 = 12,690/x
3. Step 3: Cross multiply
   7,876x = 12,690 × 12,690
4. Step 4: Simplify right side
   7,876x = 161,036,100
5. Step 5: Solve for x
   x = 161,036,100/7,876
6. Step 6: Final answer
   x = 20,446.43