Finding the Fourth Proportional to 71.78, 107.49 and 51.27

Step by Step Solution

1. Step 1: Write the proportion equation
   71.78 : 107.49 = 51.27 : x
2. Step 2: Convert to fraction form
   71.78/107.49 = 51.27/x
3. Step 3: Cross multiply
   71.78x = 107.49 × 51.27
4. Step 4: Simplify right side
   71.78x = 5,511.01
5. Step 5: Solve for x
   x = 5,511.01/71.78
6. Step 6: Final answer
   x = 76.78