Finding the Third Proportional to 83.14 and 128.72

Step by Step Solution

1. Step 1: Write the proportion equation
   83.14 : 128.72 = 128.72 : x
2. Step 2: Convert to fraction form
   83.14/128.72 = 128.72/x
3. Step 3: Cross multiply
   83.14x = 128.72 × 128.72
4. Step 4: Simplify right side
   83.14x = 16,570.03
5. Step 5: Solve for x
   x = 16,570.03/83.14
6. Step 6: Final answer
   x = 199.31