Finding the Third Proportional to 10,978 and 20,860

Step by Step Solution

1. Step 1: Write the proportion equation
   10,978 : 20,860 = 20,860 : x
2. Step 2: Convert to fraction form
   10,978/20,860 = 20,860/x
3. Step 3: Cross multiply
   10,978x = 20,860 × 20,860
4. Step 4: Simplify right side
   10,978x = 435,139,600
5. Step 5: Solve for x
   x = 435,139,600/10,978
6. Step 6: Final answer
   x = 39,637.42