Finding the Fourth Proportional to 42.72, 58.92 and 28.17

Step by Step Solution

1. Step 1: Write the proportion equation
   42.72 : 58.92 = 28.17 : x
2. Step 2: Convert to fraction form
   42.72/58.92 = 28.17/x
3. Step 3: Cross multiply
   42.72x = 58.92 × 28.17
4. Step 4: Simplify right side
   42.72x = 1,659.78
5. Step 5: Solve for x
   x = 1,659.78/42.72
6. Step 6: Final answer
   x = 38.85