Finding the Fourth Proportional to 105.79, 145.83 and 86.23

Step by Step Solution

1. Step 1: Write the proportion equation
   105.79 : 145.83 = 86.23 : x
2. Step 2: Convert to fraction form
   105.79/145.83 = 86.23/x
3. Step 3: Cross multiply
   105.79x = 145.83 × 86.23
4. Step 4: Simplify right side
   105.79x = 12,574.92
5. Step 5: Solve for x
   x = 12,574.92/105.79
6. Step 6: Final answer
   x = 118.87