Finding the Fourth Proportional to 72.96, 109.60 and 53.76

Step by Step Solution

1. Step 1: Write the proportion equation
   72.96 : 109.60 = 53.76 : x
2. Step 2: Convert to fraction form
   72.96/109.60 = 53.76/x
3. Step 3: Cross multiply
   72.96x = 109.60 × 53.76
4. Step 4: Simplify right side
   72.96x = 5,892.10
5. Step 5: Solve for x
   x = 5,892.10/72.96
6. Step 6: Final answer
   x = 80.76