Finding the Fourth Proportional to 85.83, 128.72 and 28.02

Step by Step Solution

1. Step 1: Write the proportion equation
   85.83 : 128.72 = 28.02 : x
2. Step 2: Convert to fraction form
   85.83/128.72 = 28.02/x
3. Step 3: Cross multiply
   85.83x = 128.72 × 28.02
4. Step 4: Simplify right side
   85.83x = 3,606.93
5. Step 5: Solve for x
   x = 3,606.93/85.83
6. Step 6: Final answer
   x = 42.02