Finding the Fourth Proportional to 42.18, 58.15 and 28.34

Step by Step Solution

1. Step 1: Write the proportion equation
   42.18 : 58.15 = 28.34 : x
2. Step 2: Convert to fraction form
   42.18/58.15 = 28.34/x
3. Step 3: Cross multiply
   42.18x = 58.15 × 28.34
4. Step 4: Simplify right side
   42.18x = 1,647.97
5. Step 5: Solve for x
   x = 1,647.97/42.18
6. Step 6: Final answer
   x = 39.07