Finding the Fourth Proportional to 105.06, 144.81 and 72.39

Step by Step Solution

1. Step 1: Write the proportion equation
   105.06 : 144.81 = 72.39 : x
2. Step 2: Convert to fraction form
   105.06/144.81 = 72.39/x
3. Step 3: Cross multiply
   105.06x = 144.81 × 72.39
4. Step 4: Simplify right side
   105.06x = 10,482.80
5. Step 5: Solve for x
   x = 10,482.80/105.06
6. Step 6: Final answer
   x = 99.78