Finding the Fourth Proportional to 42.72, 58.91 and 28.89

Step by Step Solution

1. Step 1: Write the proportion equation
   42.72 : 58.91 = 28.89 : x
2. Step 2: Convert to fraction form
   42.72/58.91 = 28.89/x
3. Step 3: Cross multiply
   42.72x = 58.91 × 28.89
4. Step 4: Simplify right side
   42.72x = 1,701.54
5. Step 5: Solve for x
   x = 1,701.54/42.72
6. Step 6: Final answer
   x = 39.83