Finding the Third Proportional to 81.50 and 140.50

Step by Step Solution

1. Step 1: Write the proportion equation
   81.50 : 140.50 = 140.50 : x
2. Step 2: Convert to fraction form
   81.50/140.50 = 140.50/x
3. Step 3: Cross multiply
   81.50x = 140.50 × 140.50
4. Step 4: Simplify right side
   81.50x = 19,740.25
5. Step 5: Solve for x
   x = 19,740.25/81.50
6. Step 6: Final answer
   x = 242.21