Finding the Fourth Proportional to 76.50, 105.57 and 54.72

Step by Step Solution

1. Step 1: Write the proportion equation
   76.50 : 105.57 = 54.72 : x
2. Step 2: Convert to fraction form
   76.50/105.57 = 54.72/x
3. Step 3: Cross multiply
   76.50x = 105.57 × 54.72
4. Step 4: Simplify right side
   76.50x = 5,776.79
5. Step 5: Solve for x
   x = 5,776.79/76.50
6. Step 6: Final answer
   x = 75.51