Finding the Fourth Proportional to 82.10, 123.17 and 28.00

Step by Step Solution

1. Step 1: Write the proportion equation
   82.10 : 123.17 = 28.00 : x
2. Step 2: Convert to fraction form
   82.10/123.17 = 28.00/x
3. Step 3: Cross multiply
   82.10x = 123.17 × 28.00
4. Step 4: Simplify right side
   82.10x = 3,448.00
5. Step 5: Solve for x
   x = 3,448.00/82.10
6. Step 6: Final answer
   x = 42.00