Finding the Fourth Proportional to 82.18, 123.37 and 81.77

Step by Step Solution

1. Step 1: Write the proportion equation
   82.18 : 123.37 = 81.77 : x
2. Step 2: Convert to fraction form
   82.18/123.37 = 81.77/x
3. Step 3: Cross multiply
   82.18x = 123.37 × 81.77
4. Step 4: Simplify right side
   82.18x = 10,087.96
5. Step 5: Solve for x
   x = 10,087.96/82.18
6. Step 6: Final answer
   x = 122.75