Finding the Fourth Proportional to 42.57, 58.71 and 28.74

Step by Step Solution

1. Step 1: Write the proportion equation
   42.57 : 58.71 = 28.74 : x
2. Step 2: Convert to fraction form
   42.57/58.71 = 28.74/x
3. Step 3: Cross multiply
   42.57x = 58.71 × 28.74
4. Step 4: Simplify right side
   42.57x = 1,687.33
5. Step 5: Solve for x
   x = 1,687.33/42.57
6. Step 6: Final answer
   x = 39.64