Finding the Fourth Proportional to 105.48, 145.61 and 72.86

Step by Step Solution

1. Step 1: Write the proportion equation
   105.48 : 145.61 = 72.86 : x
2. Step 2: Convert to fraction form
   105.48/145.61 = 72.86/x
3. Step 3: Cross multiply
   105.48x = 145.61 × 72.86
4. Step 4: Simplify right side
   105.48x = 10,608.05
5. Step 5: Solve for x
   x = 10,608.05/105.48
6. Step 6: Final answer
   x = 100.57