Finding the Fourth Proportional to 105.69, 158.59 and 80.00

Step by Step Solution

1. Step 1: Write the proportion equation
   105.69 : 158.59 = 80.00 : x
2. Step 2: Convert to fraction form
   105.69/158.59 = 80.00/x
3. Step 3: Cross multiply
   105.69x = 158.59 × 80.00
4. Step 4: Simplify right side
   105.69x = 12,687.89
5. Step 5: Solve for x
   x = 12,687.89/105.69
6. Step 6: Final answer
   x = 120.05