Finding the Fourth Proportional to 85.69, 128.54 and 28.69

Step by Step Solution

1. Step 1: Write the proportion equation
   85.69 : 128.54 = 28.69 : x
2. Step 2: Convert to fraction form
   85.69/128.54 = 28.69/x
3. Step 3: Cross multiply
   85.69x = 128.54 × 28.69
4. Step 4: Simplify right side
   85.69x = 3,687.81
5. Step 5: Solve for x
   x = 3,687.81/85.69
6. Step 6: Final answer
   x = 43.04