Finding the Fourth Proportional to 116.16, 160.52 and 86.78

Step by Step Solution

1. Step 1: Write the proportion equation
   116.16 : 160.52 = 86.78 : x
2. Step 2: Convert to fraction form
   116.16/160.52 = 86.78/x
3. Step 3: Cross multiply
   116.16x = 160.52 × 86.78
4. Step 4: Simplify right side
   116.16x = 13,928.69
5. Step 5: Solve for x
   x = 13,928.69/116.16
6. Step 6: Final answer
   x = 119.91