Finding the Fourth Proportional to 86.12, 129.13 and 42.83

Step by Step Solution

1. Step 1: Write the proportion equation
   86.12 : 129.13 = 42.83 : x
2. Step 2: Convert to fraction form
   86.12/129.13 = 42.83/x
3. Step 3: Cross multiply
   86.12x = 129.13 × 42.83
4. Step 4: Simplify right side
   86.12x = 5,530.37
5. Step 5: Solve for x
   x = 5,530.37/86.12
6. Step 6: Final answer
   x = 64.22