Finding the Fourth Proportional to 111.68, 167.28 and 83.12

Step by Step Solution

1. Step 1: Write the proportion equation
   111.68 : 167.28 = 83.12 : x
2. Step 2: Convert to fraction form
   111.68/167.28 = 83.12/x
3. Step 3: Cross multiply
   111.68x = 167.28 × 83.12
4. Step 4: Simplify right side
   111.68x = 13,904.31
5. Step 5: Solve for x
   x = 13,904.31/111.68
6. Step 6: Final answer
   x = 124.50