Finding the Fourth Proportional to 111.30, 166.87 and 42.79

Step by Step Solution

1. Step 1: Write the proportion equation
   111.30 : 166.87 = 42.79 : x
2. Step 2: Convert to fraction form
   111.30/166.87 = 42.79/x
3. Step 3: Cross multiply
   111.30x = 166.87 × 42.79
4. Step 4: Simplify right side
   111.30x = 7,140.15
5. Step 5: Solve for x
   x = 7,140.15/111.30
6. Step 6: Final answer
   x = 64.16