Finding the Fourth Proportional to 111.71, 154.17 and 79.11

Step by Step Solution

1. Step 1: Write the proportion equation
   111.71 : 154.17 = 79.11 : x
2. Step 2: Convert to fraction form
   111.71/154.17 = 79.11/x
3. Step 3: Cross multiply
   111.71x = 154.17 × 79.11
4. Step 4: Simplify right side
   111.71x = 12,196.39
5. Step 5: Solve for x
   x = 12,196.39/111.71
6. Step 6: Final answer
   x = 109.18