Finding the Fourth Proportional to 113.12, 168.72 and 105.92

Step by Step Solution

1. Step 1: Write the proportion equation
   113.12 : 168.72 = 105.92 : x
2. Step 2: Convert to fraction form
   113.12/168.72 = 105.92/x
3. Step 3: Cross multiply
   113.12x = 168.72 × 105.92
4. Step 4: Simplify right side
   113.12x = 17,870.82
5. Step 5: Solve for x
   x = 17,870.82/113.12
6. Step 6: Final answer
   x = 157.98