Finding the Fourth Proportional to 105.17, 145.06 and 86.83

Step by Step Solution

1. Step 1: Write the proportion equation
   105.17 : 145.06 = 86.83 : x
2. Step 2: Convert to fraction form
   105.17/145.06 = 86.83/x
3. Step 3: Cross multiply
   105.17x = 145.06 × 86.83
4. Step 4: Simplify right side
   105.17x = 12,594.98
5. Step 5: Solve for x
   x = 12,594.98/105.17
6. Step 6: Final answer
   x = 119.76