Finding the Fourth Proportional to 42.47, 63.71 and 18.42

Step by Step Solution

1. Step 1: Write the proportion equation
   42.47 : 63.71 = 18.42 : x
2. Step 2: Convert to fraction form
   42.47/63.71 = 18.42/x
3. Step 3: Cross multiply
   42.47x = 63.71 × 18.42
4. Step 4: Simplify right side
   42.47x = 1,173.54
5. Step 5: Solve for x
   x = 1,173.54/42.47
6. Step 6: Final answer
   x = 27.63