Finding the Fourth Proportional to 42.42, 58.56 and 28.64

Step by Step Solution

1. Step 1: Write the proportion equation
   42.42 : 58.56 = 28.64 : x
2. Step 2: Convert to fraction form
   42.42/58.56 = 28.64/x
3. Step 3: Cross multiply
   42.42x = 58.56 × 28.64
4. Step 4: Simplify right side
   42.42x = 1,677.16
5. Step 5: Solve for x
   x = 1,677.16/42.42
6. Step 6: Final answer
   x = 39.54