Finding the Fourth Proportional to 105.77, 145.78 and 72.96

Step by Step Solution

1. Step 1: Write the proportion equation
   105.77 : 145.78 = 72.96 : x
2. Step 2: Convert to fraction form
   105.77/145.78 = 72.96/x
3. Step 3: Cross multiply
   105.77x = 145.78 × 72.96
4. Step 4: Simplify right side
   105.77x = 10,636.11
5. Step 5: Solve for x
   x = 10,636.11/105.77
6. Step 6: Final answer
   x = 100.56