Finding the Fourth Proportional to 111.71, 167.80 and 105.59

Step by Step Solution

1. Step 1: Write the proportion equation
   111.71 : 167.80 = 105.59 : x
2. Step 2: Convert to fraction form
   111.71/167.80 = 105.59/x
3. Step 3: Cross multiply
   111.71x = 167.80 × 105.59
4. Step 4: Simplify right side
   111.71x = 17,716.90
5. Step 5: Solve for x
   x = 17,716.90/111.71
6. Step 6: Final answer
   x = 158.59