Finding the Fourth Proportional to 82.56, 114.72 and 81.72

Step by Step Solution

1. Step 1: Write the proportion equation
   82.56 : 114.72 = 81.72 : x
2. Step 2: Convert to fraction form
   82.56/114.72 = 81.72/x
3. Step 3: Cross multiply
   82.56x = 114.72 × 81.72
4. Step 4: Simplify right side
   82.56x = 9,374.92
5. Step 5: Solve for x
   x = 9,374.92/82.56
6. Step 6: Final answer
   x = 113.55