Finding the Fourth Proportional to 80.96, 111.72 and 72.32

Step by Step Solution

1. Step 1: Write the proportion equation
   80.96 : 111.72 = 72.32 : x
2. Step 2: Convert to fraction form
   80.96/111.72 = 72.32/x
3. Step 3: Cross multiply
   80.96x = 111.72 × 72.32
4. Step 4: Simplify right side
   80.96x = 8,079.59
5. Step 5: Solve for x
   x = 8,079.59/80.96
6. Step 6: Final answer
   x = 99.80