Finding the Third Proportional to 10.69 and 21.38

Step by Step Solution

1. Step 1: Write the proportion equation
   10.69 : 21.38 = 21.38 : x
2. Step 2: Convert to fraction form
   10.69/21.38 = 21.38/x
3. Step 3: Cross multiply
   10.69x = 21.38 × 21.38
4. Step 4: Simplify right side
   10.69x = 456.89
5. Step 5: Solve for x
   x = 456.89/10.69
6. Step 6: Final answer
   x = 42.75