Finding the Fourth Proportional to 42.56, 58.15 and 42.31

Step by Step Solution

1. Step 1: Write the proportion equation
   42.56 : 58.15 = 42.31 : x
2. Step 2: Convert to fraction form
   42.56/58.15 = 42.31/x
3. Step 3: Cross multiply
   42.56x = 58.15 × 42.31
4. Step 4: Simplify right side
   42.56x = 2,460.08
5. Step 5: Solve for x
   x = 2,460.08/42.56
6. Step 6: Final answer
   x = 57.81