Finding the Fourth Proportional to 142.69, 196.91 and 80.50

Step by Step Solution

1. Step 1: Write the proportion equation
   142.69 : 196.91 = 80.50 : x
2. Step 2: Convert to fraction form
   142.69/196.91 = 80.50/x
3. Step 3: Cross multiply
   142.69x = 196.91 × 80.50
4. Step 4: Simplify right side
   142.69x = 15,851.46
5. Step 5: Solve for x
   x = 15,851.46/142.69
6. Step 6: Final answer
   x = 111.09