Finding the Third Proportional to 85.78 and 134.16

Step by Step Solution

1. Step 1: Write the proportion equation
   85.78 : 134.16 = 134.16 : x
2. Step 2: Convert to fraction form
   85.78/134.16 = 134.16/x
3. Step 3: Cross multiply
   85.78x = 134.16 × 134.16
4. Step 4: Simplify right side
   85.78x = 17,997.90
5. Step 5: Solve for x
   x = 17,997.90/85.78
6. Step 6: Final answer
   x = 209.81