Finding the Fourth Proportional to 111.87, 154.16 and 105.79

Step by Step Solution

1. Step 1: Write the proportion equation
   111.87 : 154.16 = 105.79 : x
2. Step 2: Convert to fraction form
   111.87/154.16 = 105.79/x
3. Step 3: Cross multiply
   111.87x = 154.16 × 105.79
4. Step 4: Simplify right side
   111.87x = 16,308.59
5. Step 5: Solve for x
   x = 16,308.59/111.87
6. Step 6: Final answer
   x = 145.78