Finding the Third Proportional to 21.13 and 42.63

Step by Step Solution

1. Step 1: Write the proportion equation
   21.13 : 42.63 = 42.63 : x
2. Step 2: Convert to fraction form
   21.13/42.63 = 42.63/x
3. Step 3: Cross multiply
   21.13x = 42.63 × 42.63
4. Step 4: Simplify right side
   21.13x = 1,816.89
5. Step 5: Solve for x
   x = 1,816.89/21.13
6. Step 6: Final answer
   x = 86.01