Finding the Fourth Proportional to 82.56, 123.12 and 82.42

Step by Step Solution

1. Step 1: Write the proportion equation
   82.56 : 123.12 = 82.42 : x
2. Step 2: Convert to fraction form
   82.56/123.12 = 82.42/x
3. Step 3: Cross multiply
   82.56x = 123.12 × 82.42
4. Step 4: Simplify right side
   82.56x = 10,147.55
5. Step 5: Solve for x
   x = 10,147.55/82.56
6. Step 6: Final answer
   x = 122.91