Finding the Fourth Proportional to 112.89, 155.76 and 86.69

Step by Step Solution

1. Step 1: Write the proportion equation
   112.89 : 155.76 = 86.69 : x
2. Step 2: Convert to fraction form
   112.89/155.76 = 86.69/x
3. Step 3: Cross multiply
   112.89x = 155.76 × 86.69
4. Step 4: Simplify right side
   112.89x = 13,502.83
5. Step 5: Solve for x
   x = 13,502.83/112.89
6. Step 6: Final answer
   x = 119.61