Finding the Fourth Proportional to 105.46, 145.56 and 72.28

Step by Step Solution

1. Step 1: Write the proportion equation
   105.46 : 145.56 = 72.28 : x
2. Step 2: Convert to fraction form
   105.46/145.56 = 72.28/x
3. Step 3: Cross multiply
   105.46x = 145.56 × 72.28
4. Step 4: Simplify right side
   105.46x = 10,521.08
5. Step 5: Solve for x
   x = 10,521.08/105.46
6. Step 6: Final answer
   x = 99.76