Finding the Fourth Proportional to 111.32, 153.68 and 86.72

Step by Step Solution

1. Step 1: Write the proportion equation
   111.32 : 153.68 = 86.72 : x
2. Step 2: Convert to fraction form
   111.32/153.68 = 86.72/x
3. Step 3: Cross multiply
   111.32x = 153.68 × 86.72
4. Step 4: Simplify right side
   111.32x = 13,327.13
5. Step 5: Solve for x
   x = 13,327.13/111.32
6. Step 6: Final answer
   x = 119.72