Finding the Third Proportional to 12,780 and 16,978

Step by Step Solution

1. Step 1: Write the proportion equation
   12,780 : 16,978 = 16,978 : x
2. Step 2: Convert to fraction form
   12,780/16,978 = 16,978/x
3. Step 3: Cross multiply
   12,780x = 16,978 × 16,978
4. Step 4: Simplify right side
   12,780x = 288,252,484
5. Step 5: Solve for x
   x = 288,252,484/12,780
6. Step 6: Final answer
   x = 22,554.97