Finding the Fourth Proportional to 76.72, 105.82 and 57.28

Step by Step Solution

1. Step 1: Write the proportion equation
   76.72 : 105.82 = 57.28 : x
2. Step 2: Convert to fraction form
   76.72/105.82 = 57.28/x
3. Step 3: Cross multiply
   76.72x = 105.82 × 57.28
4. Step 4: Simplify right side
   76.72x = 6,061.37
5. Step 5: Solve for x
   x = 6,061.37/76.72
6. Step 6: Final answer
   x = 79.01