Finding the Fourth Proportional to 72.96, 100.73 and 57.18

Step by Step Solution

1. Step 1: Write the proportion equation
   72.96 : 100.73 = 57.18 : x
2. Step 2: Convert to fraction form
   72.96/100.73 = 57.18/x
3. Step 3: Cross multiply
   72.96x = 100.73 × 57.18
4. Step 4: Simplify right side
   72.96x = 5,759.58
5. Step 5: Solve for x
   x = 5,759.58/72.96
6. Step 6: Final answer
   x = 78.94