Finding the Fourth Proportional to 142.63, 196.82 and 87.39

Step by Step Solution

1. Step 1: Write the proportion equation
   142.63 : 196.82 = 87.39 : x
2. Step 2: Convert to fraction form
   142.63/196.82 = 87.39/x
3. Step 3: Cross multiply
   142.63x = 196.82 × 87.39
4. Step 4: Simplify right side
   142.63x = 17,200.10
5. Step 5: Solve for x
   x = 17,200.10/142.63
6. Step 6: Final answer
   x = 120.59