Finding the Fourth Proportional to 105.34, 145.21 and 72.54

Step by Step Solution

1. Step 1: Write the proportion equation
   105.34 : 145.21 = 72.54 : x
2. Step 2: Convert to fraction form
   105.34/145.21 = 72.54/x
3. Step 3: Cross multiply
   105.34x = 145.21 × 72.54
4. Step 4: Simplify right side
   105.34x = 10,533.53
5. Step 5: Solve for x
   x = 10,533.53/105.34
6. Step 6: Final answer
   x = 100.00