Finding the Third Proportional to 8,978 and 12,621

Step by Step Solution

1. Step 1: Write the proportion equation
   8,978 : 12,621 = 12,621 : x
2. Step 2: Convert to fraction form
   8,978/12,621 = 12,621/x
3. Step 3: Cross multiply
   8,978x = 12,621 × 12,621
4. Step 4: Simplify right side
   8,978x = 159,289,641
5. Step 5: Solve for x
   x = 159,289,641/8,978
6. Step 6: Final answer
   x = 17,742.22