Finding the Fourth Proportional to 67.78, 101.76 and 54.31

Step by Step Solution

1. Step 1: Write the proportion equation
   67.78 : 101.76 = 54.31 : x
2. Step 2: Convert to fraction form
   67.78/101.76 = 54.31/x
3. Step 3: Cross multiply
   67.78x = 101.76 × 54.31
4. Step 4: Simplify right side
   67.78x = 5,526.59
5. Step 5: Solve for x
   x = 5,526.59/67.78
6. Step 6: Final answer
   x = 81.54