Finding the Fourth Proportional to 76.72, 105.72 and 54.84

Step by Step Solution

1. Step 1: Write the proportion equation
   76.72 : 105.72 = 54.84 : x
2. Step 2: Convert to fraction form
   76.72/105.72 = 54.84/x
3. Step 3: Cross multiply
   76.72x = 105.72 × 54.84
4. Step 4: Simplify right side
   76.72x = 5,797.68
5. Step 5: Solve for x
   x = 5,797.68/76.72
6. Step 6: Final answer
   x = 75.57