Finding the Fourth Proportional to 72.56, 108.89 and 42.15

Step by Step Solution

1. Step 1: Write the proportion equation
   72.56 : 108.89 = 42.15 : x
2. Step 2: Convert to fraction form
   72.56/108.89 = 42.15/x
3. Step 3: Cross multiply
   72.56x = 108.89 × 42.15
4. Step 4: Simplify right side
   72.56x = 4,589.39
5. Step 5: Solve for x
   x = 4,589.39/72.56
6. Step 6: Final answer
   x = 63.25