Finding the Third Proportional to 85.64 and 128.18

Step by Step Solution

1. Step 1: Write the proportion equation
   85.64 : 128.18 = 128.18 : x
2. Step 2: Convert to fraction form
   85.64/128.18 = 128.18/x
3. Step 3: Cross multiply
   85.64x = 128.18 × 128.18
4. Step 4: Simplify right side
   85.64x = 16,430.03
5. Step 5: Solve for x
   x = 16,430.03/85.64
6. Step 6: Final answer
   x = 191.85