Finding the Fourth Proportional to 86.56, 129.04 and 82.72

Step by Step Solution

1. Step 1: Write the proportion equation
   86.56 : 129.04 = 82.72 : x
2. Step 2: Convert to fraction form
   86.56/129.04 = 82.72/x
3. Step 3: Cross multiply
   86.56x = 129.04 × 82.72
4. Step 4: Simplify right side
   86.56x = 10,674.19
5. Step 5: Solve for x
   x = 10,674.19/86.56
6. Step 6: Final answer
   x = 123.32