Finding the Fourth Proportional to 81.06, 121.59 and 42.56

Step by Step Solution

1. Step 1: Write the proportion equation
   81.06 : 121.59 = 42.56 : x
2. Step 2: Convert to fraction form
   81.06/121.59 = 42.56/x
3. Step 3: Cross multiply
   81.06x = 121.59 × 42.56
4. Step 4: Simplify right side
   81.06x = 5,174.72
5. Step 5: Solve for x
   x = 5,174.72/81.06
6. Step 6: Final answer
   x = 63.84