Finding the Fourth Proportional to 105.39, 145.29 and 72.58

Step by Step Solution

1. Step 1: Write the proportion equation
   105.39 : 145.29 = 72.58 : x
2. Step 2: Convert to fraction form
   105.39/145.29 = 72.58/x
3. Step 3: Cross multiply
   105.39x = 145.29 × 72.58
4. Step 4: Simplify right side
   105.39x = 10,545.15
5. Step 5: Solve for x
   x = 10,545.15/105.39
6. Step 6: Final answer
   x = 100.06