Finding the Third Proportional to 12,168 and 15,978

Step by Step Solution

1. Step 1: Write the proportion equation
   12,168 : 15,978 = 15,978 : x
2. Step 2: Convert to fraction form
   12,168/15,978 = 15,978/x
3. Step 3: Cross multiply
   12,168x = 15,978 × 15,978
4. Step 4: Simplify right side
   12,168x = 255,296,484
5. Step 5: Solve for x
   x = 255,296,484/12,168
6. Step 6: Final answer
   x = 20,980.97