Finding the Third Proportional to 12.88 and 20.50

Step by Step Solution

1. Step 1: Write the proportion equation
   12.88 : 20.50 = 20.50 : x
2. Step 2: Convert to fraction form
   12.88/20.50 = 20.50/x
3. Step 3: Cross multiply
   12.88x = 20.50 × 20.50
4. Step 4: Simplify right side
   12.88x = 420.25
5. Step 5: Solve for x
   x = 420.25/12.88
6. Step 6: Final answer
   x = 32.64