Finding the Fourth Proportional to 142.41, 196.56 and 87.18

Step by Step Solution

1. Step 1: Write the proportion equation
   142.41 : 196.56 = 87.18 : x
2. Step 2: Convert to fraction form
   142.41/196.56 = 87.18/x
3. Step 3: Cross multiply
   142.41x = 196.56 × 87.18
4. Step 4: Simplify right side
   142.41x = 17,136.10
5. Step 5: Solve for x
   x = 17,136.10/142.41
6. Step 6: Final answer
   x = 120.33