Finding the Fourth Proportional to 216.53, 298.56 and 142.71

Step by Step Solution

1. Step 1: Write the proportion equation
   216.53 : 298.56 = 142.71 : x
2. Step 2: Convert to fraction form
   216.53/298.56 = 142.71/x
3. Step 3: Cross multiply
   216.53x = 298.56 × 142.71
4. Step 4: Simplify right side
   216.53x = 42,607.50
5. Step 5: Solve for x
   x = 42,607.50/216.53
6. Step 6: Final answer
   x = 196.78