Finding the Fourth Proportional to 86.06, 129.02 and 42.72

Step by Step Solution

1. Step 1: Write the proportion equation
   86.06 : 129.02 = 42.72 : x
2. Step 2: Convert to fraction form
   86.06/129.02 = 42.72/x
3. Step 3: Cross multiply
   86.06x = 129.02 × 42.72
4. Step 4: Simplify right side
   86.06x = 5,511.73
5. Step 5: Solve for x
   x = 5,511.73/86.06
6. Step 6: Final answer
   x = 64.05