Finding the Fourth Proportional to 111.28, 166.78 and 42.74

Step by Step Solution

1. Step 1: Write the proportion equation
   111.28 : 166.78 = 42.74 : x
2. Step 2: Convert to fraction form
   111.28/166.78 = 42.74/x
3. Step 3: Cross multiply
   111.28x = 166.78 × 42.74
4. Step 4: Simplify right side
   111.28x = 7,128.18
5. Step 5: Solve for x
   x = 7,128.18/111.28
6. Step 6: Final answer
   x = 64.06