Finding the Fourth Proportional to 82.71, 123.97 and 28.56

Step by Step Solution

1. Step 1: Write the proportion equation
   82.71 : 123.97 = 28.56 : x
2. Step 2: Convert to fraction form
   82.71/123.97 = 28.56/x
3. Step 3: Cross multiply
   82.71x = 123.97 × 28.56
4. Step 4: Simplify right side
   82.71x = 3,540.20
5. Step 5: Solve for x
   x = 3,540.20/82.71
6. Step 6: Final answer
   x = 42.80