Finding the Fourth Proportional to 42.72, 58.94 and 28.18

Step by Step Solution

1. Step 1: Write the proportion equation
   42.72 : 58.94 = 28.18 : x
2. Step 2: Convert to fraction form
   42.72/58.94 = 28.18/x
3. Step 3: Cross multiply
   42.72x = 58.94 × 28.18
4. Step 4: Simplify right side
   42.72x = 1,660.93
5. Step 5: Solve for x
   x = 1,660.93/42.72
6. Step 6: Final answer
   x = 38.88