Finding the Fourth Proportional to 80.72, 111.37 and 51.61

Step by Step Solution

1. Step 1: Write the proportion equation
   80.72 : 111.37 = 51.61 : x
2. Step 2: Convert to fraction form
   80.72/111.37 = 51.61/x
3. Step 3: Cross multiply
   80.72x = 111.37 × 51.61
4. Step 4: Simplify right side
   80.72x = 5,747.81
5. Step 5: Solve for x
   x = 5,747.81/80.72
6. Step 6: Final answer
   x = 71.21