Finding the Fourth Proportional to 276.72, 414.33 and 139.42

Step by Step Solution

1. Step 1: Write the proportion equation
   276.72 : 414.33 = 139.42 : x
2. Step 2: Convert to fraction form
   276.72/414.33 = 139.42/x
3. Step 3: Cross multiply
   276.72x = 414.33 × 139.42
4. Step 4: Simplify right side
   276.72x = 57,765.89
5. Step 5: Solve for x
   x = 57,765.89/276.72
6. Step 6: Final answer
   x = 208.75