Finding the Fourth Proportional to 113.72, 171.59 and 109.50

Step by Step Solution

1. Step 1: Write the proportion equation
   113.72 : 171.59 = 109.50 : x
2. Step 2: Convert to fraction form
   113.72/171.59 = 109.50/x
3. Step 3: Cross multiply
   113.72x = 171.59 × 109.50
4. Step 4: Simplify right side
   113.72x = 18,789.11
5. Step 5: Solve for x
   x = 18,789.11/113.72
6. Step 6: Final answer
   x = 165.22