Finding the Fourth Proportional to 105.45, 145.50 and 72.29

Step by Step Solution

1. Step 1: Write the proportion equation
   105.45 : 145.50 = 72.29 : x
2. Step 2: Convert to fraction form
   105.45/145.50 = 72.29/x
3. Step 3: Cross multiply
   105.45x = 145.50 × 72.29
4. Step 4: Simplify right side
   105.45x = 10,517.47
5. Step 5: Solve for x
   x = 10,517.47/105.45
6. Step 6: Final answer
   x = 99.74