Finding the Fourth Proportional to 82.69, 123.20 and 80.88

Step by Step Solution

1. Step 1: Write the proportion equation
   82.69 : 123.20 = 80.88 : x
2. Step 2: Convert to fraction form
   82.69/123.20 = 80.88/x
3. Step 3: Cross multiply
   82.69x = 123.20 × 80.88
4. Step 4: Simplify right side
   82.69x = 9,964.42
5. Step 5: Solve for x
   x = 9,964.42/82.69
6. Step 6: Final answer
   x = 120.50