Finding the Fourth Proportional to 86.27, 129.39 and 28.50

Step by Step Solution

1. Step 1: Write the proportion equation
   86.27 : 129.39 = 28.50 : x
2. Step 2: Convert to fraction form
   86.27/129.39 = 28.50/x
3. Step 3: Cross multiply
   86.27x = 129.39 × 28.50
4. Step 4: Simplify right side
   86.27x = 3,687.04
5. Step 5: Solve for x
   x = 3,687.04/86.27
6. Step 6: Final answer
   x = 42.74