Finding the Third Proportional to 80.50 and 85.50

Step by Step Solution

1. Step 1: Write the proportion equation
   80.50 : 85.50 = 85.50 : x
2. Step 2: Convert to fraction form
   80.50/85.50 = 85.50/x
3. Step 3: Cross multiply
   80.50x = 85.50 × 85.50
4. Step 4: Simplify right side
   80.50x = 7,310.25
5. Step 5: Solve for x
   x = 7,310.25/80.50
6. Step 6: Final answer
   x = 90.81