Finding the Fourth Proportional to 82.71, 123.78 and 57.06

Step by Step Solution

1. Step 1: Write the proportion equation
   82.71 : 123.78 = 57.06 : x
2. Step 2: Convert to fraction form
   82.71/123.78 = 57.06/x
3. Step 3: Cross multiply
   82.71x = 123.78 × 57.06
4. Step 4: Simplify right side
   82.71x = 7,062.89
5. Step 5: Solve for x
   x = 7,062.89/82.71
6. Step 6: Final answer
   x = 85.39