Finding the Third Proportional to 83.57 and 128.61

Step by Step Solution

1. Step 1: Write the proportion equation
   83.57 : 128.61 = 128.61 : x
2. Step 2: Convert to fraction form
   83.57/128.61 = 128.61/x
3. Step 3: Cross multiply
   83.57x = 128.61 × 128.61
4. Step 4: Simplify right side
   83.57x = 16,540.62
5. Step 5: Solve for x
   x = 16,540.62/83.57
6. Step 6: Final answer
   x = 197.93