Finding the Fourth Proportional to 72.64, 108.69 and 54.55

Step by Step Solution

1. Step 1: Write the proportion equation
   72.64 : 108.69 = 54.55 : x
2. Step 2: Convert to fraction form
   72.64/108.69 = 54.55/x
3. Step 3: Cross multiply
   72.64x = 108.69 × 54.55
4. Step 4: Simplify right side
   72.64x = 5,929.04
5. Step 5: Solve for x
   x = 5,929.04/72.64
6. Step 6: Final answer
   x = 81.62