Finding the Fourth Proportional to 111.72, 153.96 and 105.74

Step by Step Solution

1. Step 1: Write the proportion equation
   111.72 : 153.96 = 105.74 : x
2. Step 2: Convert to fraction form
   111.72/153.96 = 105.74/x
3. Step 3: Cross multiply
   111.72x = 153.96 × 105.74
4. Step 4: Simplify right side
   111.72x = 16,279.73
5. Step 5: Solve for x
   x = 16,279.73/111.72
6. Step 6: Final answer
   x = 145.72