Finding the Third Proportional to 20.63 and 42.56

Step by Step Solution

1. Step 1: Write the proportion equation
   20.63 : 42.56 = 42.56 : x
2. Step 2: Convert to fraction form
   20.63/42.56 = 42.56/x
3. Step 3: Cross multiply
   20.63x = 42.56 × 42.56
4. Step 4: Simplify right side
   20.63x = 1,811.57
5. Step 5: Solve for x
   x = 1,811.57/20.63
6. Step 6: Final answer
   x = 87.83