Finding the Fourth Proportional to 81.42, 111.76 and 72.48

Step by Step Solution

1. Step 1: Write the proportion equation
   81.42 : 111.76 = 72.48 : x
2. Step 2: Convert to fraction form
   81.42/111.76 = 72.48/x
3. Step 3: Cross multiply
   81.42x = 111.76 × 72.48
4. Step 4: Simplify right side
   81.42x = 8,100.00
5. Step 5: Solve for x
   x = 8,100.00/81.42
6. Step 6: Final answer
   x = 99.48