Finding the Fourth Proportional to 105.33, 145.38 and 72.12

Step by Step Solution

1. Step 1: Write the proportion equation
   105.33 : 145.38 = 72.12 : x
2. Step 2: Convert to fraction form
   105.33/145.38 = 72.12/x
3. Step 3: Cross multiply
   105.33x = 145.38 × 72.12
4. Step 4: Simplify right side
   105.33x = 10,483.72
5. Step 5: Solve for x
   x = 10,483.72/105.33
6. Step 6: Final answer
   x = 99.54