Finding the Fourth Proportional to 82.80, 123.38 and 82.02

Step by Step Solution

1. Step 1: Write the proportion equation
   82.80 : 123.38 = 82.02 : x
2. Step 2: Convert to fraction form
   82.80/123.38 = 82.02/x
3. Step 3: Cross multiply
   82.80x = 123.38 × 82.02
4. Step 4: Simplify right side
   82.80x = 10,119.22
5. Step 5: Solve for x
   x = 10,119.22/82.80
6. Step 6: Final answer
   x = 122.21