Finding the Fourth Proportional to 82.88, 124.42 and 71.72

Step by Step Solution

1. Step 1: Write the proportion equation
   82.88 : 124.42 = 71.72 : x
2. Step 2: Convert to fraction form
   82.88/124.42 = 71.72/x
3. Step 3: Cross multiply
   82.88x = 124.42 × 71.72
4. Step 4: Simplify right side
   82.88x = 8,923.40
5. Step 5: Solve for x
   x = 8,923.40/82.88
6. Step 6: Final answer
   x = 107.67