Finding the Fourth Proportional to 80.99, 111.72 and 51.43

Step by Step Solution

1. Step 1: Write the proportion equation
   80.99 : 111.72 = 51.43 : x
2. Step 2: Convert to fraction form
   80.99/111.72 = 51.43/x
3. Step 3: Cross multiply
   80.99x = 111.72 × 51.43
4. Step 4: Simplify right side
   80.99x = 5,745.89
5. Step 5: Solve for x
   x = 5,745.89/80.99
6. Step 6: Final answer
   x = 70.95