Finding the Fourth Proportional to 31.08, 42.83 and 28.81

Step by Step Solution

1. Step 1: Write the proportion equation
   31.08 : 42.83 = 28.81 : x
2. Step 2: Convert to fraction form
   31.08/42.83 = 28.81/x
3. Step 3: Cross multiply
   31.08x = 42.83 × 28.81
4. Step 4: Simplify right side
   31.08x = 1,233.71
5. Step 5: Solve for x
   x = 1,233.71/31.08
6. Step 6: Final answer
   x = 39.69