Finding the Fourth Proportional to 72.80, 108.82 and 54.56

Step by Step Solution

1. Step 1: Write the proportion equation
   72.80 : 108.82 = 54.56 : x
2. Step 2: Convert to fraction form
   72.80/108.82 = 54.56/x
3. Step 3: Cross multiply
   72.80x = 108.82 × 54.56
4. Step 4: Simplify right side
   72.80x = 5,937.22
5. Step 5: Solve for x
   x = 5,937.22/72.80
6. Step 6: Final answer
   x = 81.56