Finding the Fourth Proportional to 82.12, 123.17 and 28.05

Step by Step Solution

1. Step 1: Write the proportion equation
   82.12 : 123.17 = 28.05 : x
2. Step 2: Convert to fraction form
   82.12/123.17 = 28.05/x
3. Step 3: Cross multiply
   82.12x = 123.17 × 28.05
4. Step 4: Simplify right side
   82.12x = 3,454.92
5. Step 5: Solve for x
   x = 3,454.92/82.12
6. Step 6: Final answer
   x = 42.07