Finding the Fourth Proportional to 82.63, 123.99 and 28.57

Step by Step Solution

1. Step 1: Write the proportion equation
   82.63 : 123.99 = 28.57 : x
2. Step 2: Convert to fraction form
   82.63/123.99 = 28.57/x
3. Step 3: Cross multiply
   82.63x = 123.99 × 28.57
4. Step 4: Simplify right side
   82.63x = 3,542.39
5. Step 5: Solve for x
   x = 3,542.39/82.63
6. Step 6: Final answer
   x = 42.87