Finding the Third Proportional to 66 and 72.56

Step by Step Solution

1. Step 1: Write the proportion equation
   66 : 72.56 = 72.56 : x
2. Step 2: Convert to fraction form
   66/72.56 = 72.56/x
3. Step 3: Cross multiply
   66x = 72.56 × 72.56
4. Step 4: Simplify right side
   66x = 5,265.32
5. Step 5: Solve for x
   x = 5,265.32/66
6. Step 6: Final answer
   x = 79.78