Finding the Third Proportional to 21.38 and 42.75

Step by Step Solution

1. Step 1: Write the proportion equation
   21.38 : 42.75 = 42.75 : x
2. Step 2: Convert to fraction form
   21.38/42.75 = 42.75/x
3. Step 3: Cross multiply
   21.38x = 42.75 × 42.75
4. Step 4: Simplify right side
   21.38x = 1,827.56
5. Step 5: Solve for x
   x = 1,827.56/21.38
6. Step 6: Final answer
   x = 85.50