Finding the Fourth Proportional to 111.86, 167.78 and 57.79

Step by Step Solution

1. Step 1: Write the proportion equation
   111.86 : 167.78 = 57.79 : x
2. Step 2: Convert to fraction form
   111.86/167.78 = 57.79/x
3. Step 3: Cross multiply
   111.86x = 167.78 × 57.79
4. Step 4: Simplify right side
   111.86x = 9,696.01
5. Step 5: Solve for x
   x = 9,696.01/111.86
6. Step 6: Final answer
   x = 86.68